Validation of the Lung Immune Prognostic Index (LIPI) as a prognostic biomarker in metastatic renal cell carcinoma

BACKGROUND

The Lung Immune Prognostic Index (LIPI) is associated with immune checkpoint inhibitors (ICI) outcomes across different solid tumors, particularly in non-small cell lung cancer. Data regarding the prognostic and/or predictive role of LIPI in metastatic renal cell carcinoma (mRCC) are still scarce. The aim of this study was to evaluate whether LIPI could be predictive of survival in mRCC patients.

METHODS

We used patient level data from three different prospective studies (NIVOREN trial: nivolumab; TORAVA trial: VEGF/VEGFR-targeted therapy (TT); CheckMate 214: nivolumab-ipilimumab vs sunitinib). LIPI was calculated based on a derived neutrophils/(leukocyte-neutrophil) ratio > 3 and lactate-dehydrogenase >upper limit of normal, classifying patients into three groups (LIPI good, 0 factors;LIPI intermediate (int), 1 factor;LIPI poor, 2 factors) and/or into two groups (LIPI good, 0 factors;LIPI int/poor, 1-2 factors) according to trial sample size. Primary and secondary endpoints were overall survival (OS) and progression-free survival (PFS).

RESULTS

In the Nivolumab dataset (n = 619), LIPI was significantly associated with OS (LIPI-good 30.1 vs 13.8 months in the LIPI int/poor; HR= 0.47) and PFS (HR=0.74). In the VEGF/VEGFR-TT dataset (n = 159), only a correlation with PFS was observed. In the CheckMate214 dataset (n = 1084), LIPI was significantly associated with OS (nivolumab-ipilimumab OS LIPI good vs int/poor: HR=0.55, p < 0.0001; sunitinib: OS LIPI good vs int/poor: 0.38, p < 0.0001) in both treatment groups in univariate and multivariate analysis.

CONCLUSIONS

Pretreatment-LIPI correlated with worse survival outcomes in mRCC treated with either ICI or antiangiogenic therapy, confirming LIPI's prognostic role in mRCC irrespective of systemic treatment used.

Renal cell carcinoma histologic subtypes exhibit distinct transcriptional profiles

Molecular profiling of clear cell RCC (ccRCC) tumors of clinical trial patients has identified distinct transcriptomic signatures with predictive value, yet data in non-clear cell variants (nccRCC) are lacking. We examined the transcriptional profiles of RCC tumors representing key molecular pathways, from a multi-institutional, real-world patient cohort, including ccRCC (n = 508) and centrally-reviewed nccRCC (n = 149) samples. ccRCC had increased angiogenesis signature scores compared to the heterogeneous group of nccRCC tumors (mean z-score 0.37 vs -0.99, P < 0.001), while cell cycle, fatty acid oxidation (FAO)/AMPK signaling, fatty acid synthesis (FAS)/pentose phosphate signature scores were increased in one or more nccRCC subtypes. Among both ccRCC and nccRCC tumors, T-effector scores statistically correlated with increased immune cell infiltration and were more commonly associated with immunotherapy-related markers (PD-L1+/TMB-High/MSI-High). In conclusion, this study provides evidence of differential gene transcriptional profiles among ccRCC vs nccRCC tumors, providing new insights for optimizing personalized and histology-specific therapeutic strategies for patients with advanced RCC.

Highly variable timing renders immunotherapy efficacy and toxicity impractical biomarkers of one another in clinical practice

Background

A useful clinical biomarker requires not only association but also a consistent temporal relationship. For instance, chemotherapy-induced neutropenia and epidermal growth-factor inhibitor-related acneiform rash both occur within weeks of treatment initiation, thereby providing information prior to efficacy assessment. Although immune checkpoint inhibitor (ICI)-associated immune-related adverse events (irAE) have been associated with therapeutic benefit, irAE may have delayed and highly variable onset. To determine whether ICI efficacy and irAE could serve as clinically useful biomarkers for predicting each other, we determined the temporal relationship between initial efficacy assessment and irAE onset in a diverse population treated with ICI.

Methods

Using two-sided Fisher exact and Cochran-Armitage tests, we determined the relative timing of initial efficacy assessment and irAE occurrence in a cohort of 155 ICI-treated patients (median age 68 years, 40% women).

Results

Initial efficacy assessment was performed a median of 50 days [interquartile range (IQR) 39-59 days] after ICI initiation; median time to any irAE was 77 days (IQR 28-145 days) after ICI initiation. Median time to first irAE was 42 days (IQR 20-88 days). Overall, 58% of any irAE and 47% of first irAE occurred after initial efficacy assessment. For clinically significant (grade ≥2) irAE, 60% of any and 53% of first occurred after initial efficacy assessment. The likelihood of any future irAE did not differ according to response (45% for complete or partial response vs. 47% for other cases; P=1). In landmark analyses controlling for clinical and toxicity follow-up, patients demonstrating greater tumor shrinkage at initial efficacy assessment were more likely to develop future grade ≥2 (P=0.05) and multi-organ (P=0.02) irAE.

Conclusions

In contrast to that seen with chemotherapy and molecularly targeted therapies, the temporal relationship between ICI efficacy and toxicity is complex and bidirectional. In practice, neither parameter can be routinely relied on as a clinical biomarker to predict the other.

Immunomodulatory response to neoadjuvant nivolumab in non-metastatic clear cell renal cell carcinoma

Novel perioperative strategies are needed to reduce recurrence rates in patients undergoing nephrectomy for high-risk, non-metastatic clear cell renal cell carcinoma (ccRCC). We conducted a prospective, phase I trial of neoadjuvant nivolumab prior to nephrectomy in 15 evaluable patients with non-metastatic ccRCC. We leveraged tissue from that cohort to elucidate the effects of PD-1 inhibition on immune cell populations in ccRCC and correlate the evolving immune milieu with anti-PD-1 response. We found that nivolumab durably induces a pro-inflammatory state within the primary tumor, and baseline immune infiltration within the primary tumor correlates with nivolumab responsiveness. Nivolumab increases CTLA-4 expression in the primary tumor, and subsequent nephrectomy increases circulating concentrations of sPD-L1, sPD-L3 (sB7-H3), and s4-1BB. These findings form the basis to consider neoadjuvant immune checkpoint inhibition (ICI) for high-risk ccRCC while the tumor remains in situ and provide the rationale for perioperative strategies of novel ICI combinations.

Examination of resistance to nivolumab monotherapy through single-cell analysis of tumors from patients enrolled in the HCRN GU16-260 study of nivolumab monotherapy

698

Background: Nivolumab (nivo) monotherapy demonstrated anti-tumor activity in treatment-naïve renal cell carcinoma (RCC) in Part A of HCRN GU16-260 across all IMDC groups and in multiple histologies. Patient tumor samples were collected to characterize the tumor-immune microenvironmental (TME) determinants of effective anti-tumor immunity with nivo. Methods: Eligible patients (with clear cell or non-clear cell histology) underwent tumor biopsy prior to and/or at resistance to nivo monotherapy. Fresh tissue fragments were cryopreserved locally and centrally processed to extract viable single-cells from the RCC TME. Single-cell RNA-sequencing (scRNA-seq) and T cell receptor (TCR)-sequencing (scTCR-seq) was performed on all tumor samples. Gene expression signatures discovered through scRNA-seq were used to interrogate previously published bulk transcriptomic data from the CheckMate-009/010/025 trials of nivo in the treatment-refractory setting. Results: In total, 72,730 viable single-cells (56,900 immune and 15,830 tumor or stromal cells) were sequenced from 17 patients (8 with baseline only, 7 with progression only, and 2 with paired baseline and progression samples) across 7 trial sites. Trajectory inference analysis of tumor-infiltrating T cells revealed a bifurcating trajectory, starting with naïve T cells and ending either in PMCH+ terminally exhausted CD8+ T cells or SLAMF7+ CD8+ T cells. Notably, the SLAMF7+ T cell population expressed high levels of cytotoxic genes (including GZMA, GZMB, GNLY) and markers of tissue residency ( ZNF683/HOBIT and ITGAE/CD103), and had a restricted TCR diversity (normalized Shannon index = 0.57). Among patients with at least 100 sequenced T cells (n = 14), a higher percentage of SLAMF7+ CD8+ T cells (relative to total T cells) was associated with primary resistance (progressive disease [PD] as best response) to nivo (mean percentage in PD [n = 4] patients 32.7%; stable disease [n = 4] patients, 9.1%; complete or partial response [CR/PR; n = 6] patients, 2.2%; p = 0.019 for CR/PR vs PD). A signature derived using genes expressed in the T cell trajectory branch containing the SLAMF7+ CD8+ T cell population was used to interrogate bulk RNA-seq data from 172 pre-treatment tumors from the nivo arms of the CheckMate-009/010/025 trials. The signature score was enriched in patients with PD compared to CR/PR as best response (p = 0.032). Analysis of bulk whole exome sequencing and RNA-seq from patients enrolled in the HCRN GU16-260 is pending. Conclusions: Single-cell transcriptomic analysis uncovered a SLAMF7+ CD8 + T cell population with markers of cytotoxicity and tissue residency that was associated with resistance to nivo monotherapy in RCC. Further, the study highlights that scRNA-seq is a viable scientific strategy for deep correlative analysis in multicenter clinical trials.

Treatment-free survival (TFS) outcomes from the phase II study of nivolumab and salvage nivolumab + ipilimumab in advanced clear cell renal cell carcinoma (aRCC) (HCRN GU16-260-Cohort A)

604

Background: Treatment with immunotherapy can be associated with prolonged disease control after discontinuation without the need for further anticancer therapy. Toxicity from therapy can also persist after cessation. TFS with and without toxicity can characterize survival time. Significant TFS was reported for CheckMate 067 trial in pts with metastatic melanoma (Regan et al JITC 2021) and CheckMate 214 trial for pts with aRCC (Regan et al CCR 2021), but treatment was often halted for toxicity rather than a pre-defined treatment endpoint. We therefore sought to assess TFS in the HCRN GU16 260 trial, which was designed to reduce toxicity and to cap immunotherapy duration (Atkins et al JCO 2022). Methods: Data were analyzed from 128 patients (pts) with clear-cell aRCC treated with first-line nivolumab (NIVO) monotherapy for up to 2 years. As part of the protocol, salvage nivolumab/ipilimumab (NIVO/IPI) for up to 1 year was provided to eligible patients with disease progression at any point or stable disease at 48 weeks (28% of pts). TFS was defined as the area between Kaplan-Meier curves for time from registration to protocol therapy cessation and for time from registration to subsequent therapy initiation or death, estimated from 36-month (mo) mean times. The time on treatment or off treatment with grade 3+ treatment-related adverse events (TRAEs) was also captured. Results: At 36 mos from enrollment, 68.3% of pts were alive: 96.8% of IMDC favorable-risk (FAV) pts and 56.6% of those with intermediate/poor-risk (I/P), respectively. The 36-mo mean time on protocol therapy was 11.5 mos (16.0 mos for FAV pts and 9.6 mos for I/P pts). The 36-mo mean TFS for the whole population was 9.4 mos. For FAV pts the mean TFS was 12.9 mos, of which TFS with grade 3+ TRAEs was 1.5 mos. For I/P pts, the mean TFS was 8.0 mos, of which TFS with grade 3+ TRAEs was 1.0 mos. At 36 mos, 65.6% of FAV pts and 27.1% of I/P pts were alive and second-line treatment-free. Conclusions: NIVO monotherapy with salvage NIVO/IPI in non-responders is an active treatment approach in treatment-naïve pts with aRCC and results in substantial TFS and toxicity-free TFS. TFS was particularly noted in pts with FAV disease, further supporting the use of an immunotherapy-only regimen in this population. Clinical trial information: NCT03117309 . [Table: see text]

A phase 1b/2 study of batiraxcept (AVB-S6-500) in combination with cabozantinib in patients with advanced or metastatic clear cell renal cell carcinoma (ccRCC)

666

Background: Activation of the GAS6/AXL pathway promotes tumor cell proliferation; high levels of GAS6 and AXL have been associated with drug resistance and decreased survival. Batiraxcept is an ultra-high affinity decoy protein that captures GAS6, preventing it from activating AXL signaling. Serum soluble AXL (sAXL)/GAS6 ratio correlates with response to batiraxcept in advanced ovarian cancer. Batiraxcept in combination with cabozantinib is being evaluated in patients (pts) with metastatic clear cell renal cell carcinoma (ccRCC) in this study. Prior studies of cabozantinib in similar pt populations have shown an overall response rate (ORR) ranging from 15 – 32.5% and progression-free survival (PFS) from 3.7-7.2 months (mo). Methods: Key eligibility criteria include previously treated ccRCC pts, excluding prior cabozantinib. Objectives were to determine the safety of batiraxcept plus cabozantinib 60 mg, the recommended phase 2 dose (RP2D), ORR, PFS, duration of response. Correlative endpoints included assessment of baseline serum sAXL/GAS6 with ORR and PFS. Results: In Phase 1b (P1b), 26 pts received at least one dose of batiraxcept with cabozantinib (16 pts - 15 mg/kg; 10 pts - 20 mg/kg). Median age was 60 (range 40-81), male 85% (n=22), IMDC intermediate/poor risk 77% (n=20). All pts received prior immuno-oncology (IO) therapy, 54% (n=14) also received VEGF-TKI; 85% (n=22) received 1 to 2 prior lines of therapy (range 1-6). Median follow-up time was 11.6 mo (range 3.7-18). The RP2D is 15 mg/kg. Related adverse events (AE) any grade and grade ≥ 3 were 100% and 39% (n=10), respectively. Cabozantinib dose reductions occurred in 54% (n=14). AEs of special interest were grade 1 or 2 infusion related reactions, 27% (n=7). Batiraxcept was discontinued due to disease progression 62% (n=16) or toxicity 12% (n=3). The table shows P1b efficacy, ORR of 42%, median PFS of 9.3 mo, and DCR of 84%. Twenty (77%) pts had high baseline sAXL/GAS6 levels; ORR was 55% (11/20) with mPFS of 9.3 mo, compared to 0% ORR and mPFS 6.4 mo in the low sAXL/GAS6 pts. Conclusions: Batiraxcept was well tolerated when combined with cabozantinib. No new safety signals were noted. Efficacy for the combination is encouraging compared to historical cabozantinib monotherapy data. Higher GAS6 levels were predictive for treatment response. The P2 accrual is complete and efficacy data are maturing. A P3 trial plans to evaluate the efficacy in ccRCC patients who have progressed on IO-based and VEGF-TKI therapies. Clinical trial information: NCT04300140 . [Table: see text]

Immunomodulatory response to neoadjuvant nivolumab in non-metastatic clear cell renal cell carcinoma

708

Background: Novel perioperative strategies are needed to reduce recurrence rates in patients undergoing nephrectomy for high-risk, non-metastatic clear cell renal cell carcinoma (ccRCC). We sought to (1) elucidate the effects of PD-1 inhibition on primary tumor-infiltrating and circulating immune cell populations in ccRCC and (2) correlate tumor microenvironment and circulating immune cell compositions with response to anti-PD-1 therapy. Methods: We conducted a prospective, phase I trial of neoadjuvant nivolumab prior to nephrectomy in 15 evaluable patients with non-metastatic ccRCC. We leveraged tissue from this cohort to elucidate the effects of PD-1 inhibition on immune cell populations in ccRCC and correlate the evolving immune milieu with anti-PD-1 response using fluorescence-activated cell sorting, bulk RNA sequencing with protein activity inference, and enzyme-linked immunosorbent assay for circulating cytokines. Results: We found that nivolumab durably promotes a pro-inflammatory state within the primary tumor, as evidenced by a sustained increase in the effector T cell phenotype and decreased representation of regulatory T cell subsets. Baseline immune infiltration within the primary tumor including T effector and myeloid enrichment along with angiogenic depletion correlates with nivolumab responsiveness. Nivolumab increases CTLA-4 expression in the primary tumor, and subsequent nephrectomy increases circulating concentrations of sPD-L1, sPD-L3 (sB7-H3), and s4-1BB. Conclusions: Our findings form the basis to consider neoadjuvant immune checkpoint inhibition (ICI) for high-risk ccRCC while the tumor remains in situ and provide the rationale for perioperative strategies of novel ICI combinations. Clinical trial information: NCT02575222 .

Abstract 1258: Elevated serum DC-HIL is associated with poor response to immune checkpoint inhibitors (ICI) in metastatic renal cell carcinoma (mRCC)

ICI therapy has shown unprecedented clinical outcomes in mRCC patients, but durable responses have been limited by innate (never respond initially) and acquired resistance (initially respond but eventually develop cancer progression). Establishment of predictive biomarkers for response to ICI maximizes the therapeutic benefit. Since no such marker exists, we investigated DC-HIL/GPNMB as a possibility because we detected DC-HIL to be elevated in blood of patients with metastasis, as both a receptor on myeloid-derived suppressor cells (MDSC) and as a soluble form (sDC-HIL); and found DC-HIL to be relevant to ICI resistance in mice. We studied 27 mRCC patients treated with combination ICI (Ab to PD1/PDL1/CTLA4) and assessed tumor response (by RECIST) at 12 wk after therapy. Blood was collected before and after treatment and assayed by FACS for expression of DC-HIL and PDL1 on CD14+HLA-DRno/lo monocytic (mMDSC) and CD15+CD11b+ granulocytic MDSC (gMDSC). T-cell suppressor function was assayed by cell culture. We showed both MDSC subsets to express DC-HIL predominantly over PDL1. We also showed mMDSC to be more potent T-cell suppressors than gMDSC (85% vs. 58% suppression, p=0.012) and to also be more dependent on DC-HIL for such suppression (56% vs. 15% restoration of T-cell function after adding DC-HIL mAb, p=0.013). However, there was no significant difference in % DC-HIL+MDSC/PBMC between ICI responders and non-responders (p=0.15). We next examined the relationship between tumor response (at 12 wk) and blood sDC-HIL (by ELISA) in 31 mRCC patients. At baseline, non-responders (n=10) had a significantly higher sDC-HIL than responders (n=21) (14 ± 2.4 vs. 10 ± 4.6 ng/ml, p=0.004), but no difference in blood PDL1 or VEGF. Among initial responders (n=22), 50% maintained a positive response while the other half acquired resistance after 20 wk. Among initial non-responders (n=9), 77% never responded while 22% responded positively after 20 wk. We then analyzed changes over time in sDC-HIL levels after treatment (up to 60 wks) in individuals. Patients who responded positively to ICI at treatment inception and through 40 wk maintained blood sDC-HIL at levels lower than the median for all positive responders. Initial responders who acquired resistance (9 out of 11 patients) had low blood sDC-HIL that rose during cancer progression. All constant non-responders (n=7) had high blood sDC-HIL that remained high during the study. To our surprise, the 2 initial non-responders who responded positively after 20-40 wk of ICI displayed an abrupt rise in blood sDC-HIL during their positive response. Our results indicate blood sDC-HIL as a promising biomarker for prognosticating response to ICI in mRCC patients.

Citation Format: Jin-Sung Chung, Vijay Ramani, Ponciano D. Cruz, Hans J. Hammers, Kiyoshi Ariizumi. Elevated serum DC-HIL is associated with poor response to immune checkpoint inhibitors (ICI) in metastatic renal cell carcinoma (mRCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1258.

A phase 1b/2 study of batiraxcept (AVB-S6-500) in combination with cabozantinib, cabozantinib and nivolumab, and as monotherapy in patients with advanced or metastatic clear cell renal cell carcinoma (NCT04300140)

TPS4599

Background: In clear cell renal cell carcinoma (ccRCC) the constitutive expression of hypoxia induced factor 1-α leads to increased expression of AXL. AXL overexpression has been associated with the development of resistance to VEGF inhibitors and suppression of the innate immune response through inhibition of macrophage-driven inflammation. Batiraxcept is a recombinant fusion protein dimer containing an extracellular region of human AXL combined with the human immunoglobulin G1 heavy chain (Fc), which demonstrates highly potent, specific AXL inhibition. In preclinical studies using the 786-O, M62, and SN12L1 tumors, batiraxcept monotherapy resulted in a significant reduction of tumor growth compared to control. In healthy volunteer and ovarian cancer clinical studies, batiraxcept was well tolerated with no dose-related adverse events, and a maximum tolerated dose was not reached. Therefore, batiraxcept could be tested as either a monotherapy or in combination with standard of care drugs in patients with metastatic ccRCC. The Phase 1b dose-escalation portion of this study evaluated batiraxcept in combination with standard of care cabozantanib in patients who progressed on or after first line therapy. No DLT was observed at either of two batiraxcept doses evaluated. The recommended Phase 2 dose of batiraxcept has been identified as 15 mg/kg every 2 weeks (q2w) with cabozantinib 60 mg based upon safety, PK/PD, and preliminary efficacy data. Methods: This Phase 2, multi-center, open-label study includes three parts: Part A) batiraxcept 15 mg/kg q2w in combination with cabozantinib 60 mg daily for ccRCC subjects who have progressed on or after one line of therapy, n=25. Part B) batiraxcept 15 mg/kg q2w with cabozantinib 40 mg daily and nivolumab at the investigator’s choice (240 mg q2w or 480 mg q4w) for first line treatment of advanced or metastatic ccRCC subjects, n=20. If no safety signals are observed in the first 6 subjects enrolled, 10 subjects will be enrolled in the first stage of a Simon 2-stage minmax statistical design. If ≥ 6/10 subjects achieve PR or CR, stage 2 will open to enroll up to 20 total subjects. Part C) batiraxcept 15 mg/kg q2w monotherapy for subjects with advanced/metastatic ccRCC ineligible for curative intent therapies, n=10. The primary objective for each arm is objective response rate by RECIST v1.1. Secondary objectives include safety, duration of response, clinical benefit rate, progression free survival by RECIST v1.1, and overall survival. Exploratory objectives include pharmacokinetic and pharmacodynamic assessments. The Phase 2 portion of this Ph1b/2 study is currently enrolling. Clinical trial information: NCT04300140.

Prognostic value of the lung immune prognostic index in patients with untreated advanced renal cell carcinoma (aRCC) receiving nivolumab plus ipilimumab (N+I) or sunitinib (SUN) in the CheckMate 214 trial

4538

Background: The Lung Immune Prognostic Index (LIPI), defined by lactate dehydrogenase (LDH) and derived neutrophil to lymphocyte ratio (dNLR), has been shown to correlate with outcomes of immune checkpoint inhibitor therapy in patients (pts) with lung and other cancers, including pts with previously treated aRCC receiving nivolumab in the phase 2 NIVOREN GETUG-AFU 26 trial. We report an analysis of LIPI in pts with previously untreated aRCC receiving N+I or SUN in the randomized phase 3 CheckMate 214 trial with 5 years minimum follow-up. Methods: Data were used from CheckMate 214 comparing N+I (N 3 mg/kg + I 1 mg/kg) vs SUN (50 mg) for untreated aRCC (N = 1096). Pts with available LIPI data were categorized into 3 LIPI groups (good [LG], dNLR ≤ 3 and LDH ≤ upper limit of normal [ULN]); intermediate [LI], dNLR > 3 or LDH > ULN; and poor [LP], dNLR > 3 and LDH > ULN). This analysis focused on the prognostic value of LIPI using overall survival (OS) outcomes. Univariable analyses (UVAs) were conducted to evaluate LIPI groups alongside known risk factors including age, sex, IMDC risk, baseline PD-L1 status, prior nephrectomy, and baseline tumor burden. Variables that were statistically significant in UVAs ( P < 0.1) were included in the full multivariable analyses (MVAs), from which a reduced model was generated. Results: A total of 1085 pts were evaluable for LIPI (N+I, n = 542; SUN, n = 543). Pts were distributed evenly between treatment arms for all 3 LIPI groups, but distribution between LIPI groups was unbalanced, with most pts grouped as LG (Table). OS outcomes were improved with N+I over SUN across all LIPI groups. Moreover, pts in the LG group had better OS outcomes vs pts in the LI or LP groups regardless of treatment, but with more distinct differences between LIPI groups in the SUN arm (Table). Final MVA results showed the LIPI correlated with OS for LI vs LG in the N+I arm and for LI vs LG and LP vs LG in the SUN arm (Table). Conclusions: These results from CheckMate 214 indicate the potential prognostic value of the LIPI in pts with untreated aRCC receiving N+I or SUN. Additional analyses are ongoing to further investigate the prognostic value of LIPI in this pt population and its impact on other clinical outcomes. Clinical trial information: NCT02231749. [Table: see text]

First-in-human study of SRF388, a first-in-class IL-27 targeting antibody, as monotherapy and in combination with pembrolizumab in patients with advanced solid tumors

2501

Background: The immunoregulatory cytokine IL-27 upregulates inhibitory immune checkpoint receptors (eg, PD-L1, TIGIT) and downregulates proinflammatory cytokines (eg, IFNγ, TNFα). SRF388 is a fully human IgG1 blocking antibody to IL-27 with potential to promote immune activation in the tumor microenvironment. A phase 1 study was conducted to establish the preliminary safety of SRF388 and to identify recommended phase 2 doses (RP2D) suitable for monotherapy and combination expansions (NCT04374877). Methods: The dose-escalation study (accelerated single patient followed by standard 3+3) enrolled patients (pts) with advanced treatment-refractory solid tumors. Upon RP2D selection, monotherapy and combination expansions opened for treatment-refractory clear cell renal cell cancer (ccRCC), hepatocellular cancer (HCC), and non-small cell lung cancer. SRF388 was administered IV every 4 weeks (wks) as monotherapy and every 3 wks with pembrolizumab. Tumor response was assessed by RECIST1.1. Results: The monotherapy dose-escalation enrolled 29 pts with doses ranging from 0.003 to 20 mg/kg. Median age was 64 years. Most pts were female (62%) with ECOG PS of 1 (72%). Approximately 80% had prior PD-(L)1 blockade, and 48% had ≥4 prior therapies. Treatment-related adverse events (TRAEs) occurred in 21%, and all were low grade. Fatigue was the only TRAE reported in ≥10% (n = 3). No dose-limiting toxicities (DLTs) or Grade ≥3 TRAEs were observed. Median time on study was 9 wks (range 0–59). One patient with highly treatment-refractory NSCLC experienced a confirmed partial response (PR) at 8 wks that was durable for 20 wks. Nine pts (31%) experienced disease stabilization at 8 wks, with 6 of 9 exhibiting durable disease control at 6 months. Of the 7 pts with ccRCC in the dose-escalation portion of the trial, 3 (43%) experienced durable disease control for ≥20 wks (range: 20-32). With doses up to 20 mg/kg, SRF388 PK remain linear with an estimated T1/2 of 10-12 days. PK characteristics and safety profile support dosing every 3 or 4 wks. Based on safety, tolerability, PK, peripheral pSTAT1 inhibition, and preliminary efficacy, 10 mg/kg was selected as the RP2D. Both the pembrolizumab safety cohort (n = 10) and Stage 1 of the ccRCC monotherapy expansion (n = 17) have fully enrolled. Of the 10 evaluable pts with ccRCC, 1 confirmed monotherapy PR has been reported, enabling Stage 2 initiation. Changes in several serum cytokines and chemokines were observed after SRF388 administration, including expected increase in circulating IL-27 levels. Conclusions: Results of IL-27 pathway blockade with a first-in-class therapeutic demonstrates that SRF388 has good tolerability with encouraging preliminary antitumor activity as a monotherapy. Updated data, including safety and clinical outcomes as well as correlative biomarker analyses, will be presented. Clinical trial information: NCT04374877.

A phase 1b/2 study of batiraxcept (AVB-S6-500) in combination with cabozantinib in patients with advanced or metastatic clear cell renal cell (ccRCC) carcinoma who have received front-line treatment (NCT04300140)

4511

Background: AXL is up-regulated by hypoxia-inducible factor-1 signaling in both VHL-deficient and hypoxic tumor cells and plays a critical role in the metastatic phenotype of ccRCC. Batiraxcept is a recombinant fusion protein containing an extracellular region of human AXL combined with the human immunoglobulin G1 heavy chain (Fc), demonstrating highly potent, specific AXL inhibition. Methods: Batiraxcept at doses of 15 and 20 mg/kg, plus cabozantinib 60 mg daily, was evaluated using a 3+3 dose escalation study design. The primary objective was safety; secondary and exploratory objectives included identification of the recommended phase 2 dose (RP2D), overall response rate (ORR), and duration of response (DOR). Correlation of serum soluble AXL (sAXL)/GAS6 with ORR was evaluated. Key eligibility criteria include previously treated (2L+) ccRCC patients; prior treatment with cabozantanib was not allowed. sAXL/GAS6 was evaluated at baseline. Results: Data as of 4-February-2022, Phase 1b enrolled 26 patients, 16 patients treated with 15 mg/kg and 10 patients with 20 mg/kg dose of batiraxcept. Baseline characteristics: median age 60 (40-81); male 22 (85%); median prior line of therapy 1 (1-5); IMDC risk group of favorable 6 (23%); prior VEGF inhibitor 15 (58%); 100% with prior immunotherapy. At median follow up of 4.9 months, 92% (n=24) patients remained on the study. No dose limiting toxicities were observed at either 15 mg/kg or 20 mg/kg dose. Batiraxcept and cabozantinib related adverse events (AEs) occurred in 17 subjects (65%). Most common related AE include decreased appetite 31% (n=8), diarrhea and fatigue 23% (n=6). Grade 3 related AEs occurred in 4 patients (15%) including diarrhea, thromboembolism, hypertension, small bowel obstruction, and thrombocytopenia (n=1, 4% each) being most common. No grade 4 or 5 related AEs were observed. The ORR was 46% (n=12, partial response [PR]; Table). No patients had primary progressive disease. Among the patients who had baseline sAXL/GAS6 ratio of ≥ 2.3, the ORR was 67% (12/18). Regardless of baseline sAXL/GAS6 ratio, 3-month DOR was 100%; and 6-month progression free survival was 79%. Batiraxcept PK levels were similar across both doses and GAS6 levels suppressed through the dosing period. Conclusions: Batiraxcept plus cabozantinib is well tolerated. The RP2D of batiraxcept was identified as 15 mg/kg. Early efficacy signals were observed including 100% DOR at 3 months. Baseline sAXL/GAS6 may serve as a potential biomarker to enrich the population. Clinical trial information: NCT04300140. [Table: see text]

Chronic Use of Proton Pump Inhibitors Is Associated With an Increased Risk of Immune Checkpoint Inhibitor Colitis in Renal Cell Carcinoma

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have become a standard of care in metastatic renal cell carcinoma (mRCC) but are associated with immune-related adverse events (irAEs) including colitis. Growing evidence suggests proton pump inhibitors (PPIs) increase the risk of inflammatory bowel disease (IBD). Given the pathophysiological overlap between IBD and ICI colitis, we sought to evaluate the relationship between PPI use and ICI colitis in mRCC patients.

PATIENTS AND METHODS

We performed a retrospective study of adult patients who received ICI therapy for mRCC between 2015 and 2018 at University of Texas Southwestern Medical Center affiliated hospitals. Clinical characteristics, oncological outcomes, ICI colitis details, and PPI use details were collected by manual chart review. The diagnosis of ICI colitis was made via biopsy when available, or by clinical criteria (symptoms and response to immunosuppressive therapy) when biopsy specimens were unavailable or inconclusive. Univariable and multivariable logistic regression analyses were conducted to assess the potential contribution of PPIs to ICI colitis.

RESULTS

A total of 176 patients received ICI therapy for mRCC, of which 16 (9.1%) were diagnosed with ICI colitis. Patients with ICI colitis presented with elevated stool lactoferritin and calprotectin and a wide range of endoscopic and histologic findings. There were no significant differences between patients with and without ICI colitis in age, gender, medical comorbidities, RCC history, and overall survival. However, exposure to ipilimumab and PPI use were more frequently observed in patients with ICI colitis than those without. In univariable and multivariable logistic regression analyses, exposure to ipilimumab and chronic use of PPIs > 8 weeks were significantly associated with ICI colitis.

CONCLUSION

In addition to ipilimumab use, chronic use of PPIs may be associated with ICI colitis in patients with mRCC.

TiNivo-2: A phase 3, randomized, controlled, multicenter, open-label study to compare tivozanib in combination with nivolumab to tivozanib monotherapy in subjects with renal cell carcinoma who have progressed following one or two lines of therapy where one line has an immune checkpoint inhibitor

TPS4605

Background: Tivozanib, a highly selective and potent vascular endothelial growth factor receptor tyrosine kinase inhibitor, has demonstrated single-agent efficacy in advanced renal cell carcinoma (aRCC) along with minimal off-target toxicities and a favorable adverse event (AE) profile (Rini et al Lancet Oncol 2020). Tivozanib was approved by the FDA on March 10, 2021, for the treatment of patients with aRCC who had progressed on 2 or more prior systemic therapies. Tivozanib was combined with Nivolumab in the phase 1b/2 TiNivo trial (NCT03136627), showing an objective response rate of 56%, disease control rate of 96%, median PFS of 18.9 months and a tolerable safety profile (Albiges et al Ann Oncol. 2021). Methods: TiNivo-2 (NCT04987203) is a phase 3, randomized, controlled, multicenter, open-label study to compare tivozanib in combination with nivolumab to tivozanib monotherapy in subjects with renal cell carcinoma who have progressed following 1-2 lines of therapy including an immune checkpoint inhibitor. Eligibility criteria include age >18 years, clear cell RCC, ECOG PS 0-1, and disease progression during or following at least 6 weeks of treatment with ICI for RCC. Subjects will be stratified by IMDC risk category and whether ICI was received in most recent line of treatment or not. Subjects will receive tivozanib 1.34 mg orally once daily for 21 consecutive days followed by 7 days off, on the monotherapy arm, and tivozanib 0.89 mg at the same schedule in addition to nivolumab 480mg intravenously every 4 weeks on the combination arm. Study assessments include CT scan or MRI of the chest, abdomen, and pelvis every 8 weeks following Cycle 1 Day 1 for 2 years and every 12 weeks thereafter until disease progression is confirmed by independent radiology review (IRR). The primary objective is to compare the progression-free survival (PFS) of tivozanib in combination with nivolumab to tivozanib. A sample size of 326 subjects, with 191 events will provide at least 80% power to detect a 50% improvement in PFS, 12 mos v. 8 mos, as assessed by an IRR. Secondary endpoints include assessment of overall survival (OS), objective response rate (ORR), and duration of response (DoR), as well as safety and tolerability. Exploratory endpoints are to assess the quality of life (FKSI-DRS and EORTC QLQ C-30) and to investigate the pharmacokinetics of tivozanib. TiNivo-2 is actively enrolling and planning to open at 190 sites in the United States, and the European Union. Clinical trial information: NCT04987203.

Conditional survival and long-term efficacy with nivolumab plus ipilimumab versus sunitinib in patients with advanced renal cell carcinoma

BACKGROUND

Conditional survival estimates provide critical prognostic information for patients with advanced renal cell carcinoma (aRCC). Efficacy, safety, and conditional survival outcomes were assessed in CheckMate 214 (ClinicalTrials.gov identifier NCT02231749) with a minimum follow-up of 5 years.

METHODS

Patients with untreated aRCC were randomized to receive nivolumab (NIVO) (3 mg/kg) plus ipilimumab (IPI) (1 mg/kg) every 3 weeks for 4 cycles, then either NIVO monotherapy or sunitinib (SUN) (50 mg) daily (four 6-week cycles). Efficacy was assessed in intent-to-treat, International Metastatic Renal Cell Carcinoma Database Consortium intermediate-risk/poor-risk, and favorable-risk populations. Conditional survival outcomes (the probability of remaining alive, progression free, or in response 2 years beyond a specified landmark) were analyzed.

RESULTS

The median follow-up was 67.7 months; overall survival (median, 55.7 vs 38.4 months; hazard ratio, 0.72), progression-free survival (median, 12.3 vs 12.3 months; hazard ratio, 0.86), and objective response (39.3% vs 32.4%) benefits were maintained with NIVO+IPI versus SUN, respectively, in intent-to-treat patients (N = 550 vs 546). Point estimates for 2-year conditional overall survival beyond the 3-year landmark were higher with NIVO+IPI versus SUN (intent-to-treat patients, 81% vs 72%; intermediate-risk/poor-risk patients, 79% vs 72%; favorable-risk patients, 85% vs 72%). Conditional progression-free survival and response point estimates were also higher beyond 3 years with NIVO+IPI. Point estimates for conditional overall survival were higher or remained steady at each subsequent year of survival with NIVO+IPI in patients stratified by tumor programmed death ligand 1 expression, grade ≥3 immune-mediated adverse event experience, body mass index, and age.

CONCLUSIONS

Durable clinical benefits were observed with NIVO+IPI versus SUN at 5 years, the longest phase 3 follow-up for a first-line checkpoint inhibitor-based combination in patients with aRCC. Conditional estimates indicate that most patients who remained alive or in response with NIVO+IPI at 3 years remained so at 5 years.

TiNivo-2: A phase 3, randomized, controlled, multicenter, open-label study to compare tivozanib in combination with nivolumab to tivozanib monotherapy in subjects with renal cell carcinoma who have progressed following one or two lines of therapy where one line has an immune checkpoint inhibitor

TPS405

Background: Tivozanib, a highly selective and potent vascular endothelial growth factor receptor tyrosine kinase inhibitor, has demonstrated single-agent efficacy in advanced renal cell carcinoma (aRCC) along with minimal off-target toxicities and a favorable adverse event (AE) profile (Rini et al. Lancet Oncol 2020; 21:95-104). Tivozanib was approved by the FDA on March 10, 2021, for the treatment of patients with aRCC who had progressed on 2 or more prior lines of therapy. Tivozanib was combined with Nivolumab in the TiNivo trial (NCT03136627), showing an objective response rate of 56%, disease control rate of 96%, median PFS of 18.9 months and a favorable safety profile (Albiges et al. Ann Oncol. 2021 Jan;32(1):97-102). Methods: TiNivo-2 (NCT04987203) is a phase 3, randomized, controlled, multicenter, open-label study to compare tivozanib in combination with nivolumab to tivozanib monotherapy in subjects with renal cell carcinoma who have progressed following 1-2 lines of therapy including an immune checkpoint inhibitor. Eligibility criteria include age >18 years, clear cell RCC, ECOG PS 0-1, and disease progression during or following at least 6 weeks of treatment with ICI for RCC. Subjects will be stratified by IMDC risk category and whether ICI was received in most recent line of treatment or not. On both arms, subjects will receive Tivozanib 1.34 mg orally once daily for 21 consecutive days followed by 7 days off. In the combination arm, subjects will also receive Nivolumab 480mg intravenously every 4 weeks. Study assessments include CT scan or MRI of the chest, abdomen, and pelvis every 8 weeks following Cycle 1 Day 1 for 2 years and every 12 weeks thereafter until disease progression is confirmed by independent radiology review. The primary objective is to compare the progression-free survival (PFS) of tivozanib in combination with nivolumab to tivozanib. A sample size of 326 subjects, with 191 events will provide at least 80% power to detect a 50% improvement in PFS, 12 mos v. 8 mos, as assessed by an IRR. Secondary endpoints include assessment of overall survival (OS), objective response rate (ORR), and duration of response (DoR), as well as safety and tolerability. Exploratory endpoints are to assess the quality of life (FKSI-DRS and EORTC QLQ C-30) and to investigate the pharmacokinetics of tivozanib. TiNivo-2 is actively enrolling and planning to open at 190 sites in the United States, and the European Union. Clinical trial information: NCT04987203.

Phase 1b/2 umbrella study of investigational immune and targeted combination therapies for patients with advanced clear cell renal cell carcinoma (ccRCC)

TPS404

Background: New treatments for first and subsequent lines of therapy for ccRCC are needed. An adaptive, open-label, rolling-arm, multicenter, phase 1b/2 umbrella platform trial in advanced ccRCC is being conducted to evaluate the safety and efficacy of multiple combinations of investigational agents targeting CTLA-4 (quavonlimab [MK-1308]), hypoxia-inducible factor 2α (belzutifan [MK-6482]), lymphocyte-activation gene 3 (favezelimab [MK-4280]), immunoglobulinlike transcript 4 (MK-4830), PD-1 (pembrolizumab), and vascular endothelial growth factor–tyrosine kinase inhibitor (VEGF-TKI; lenvatinib) for advanced ccRCC. Substudy 03A (NCT04626479) will evaluate first-line therapy combinations, and substudy 03B (NCT04626518) will evaluate therapies in patients experiencing progression on PD-1/PD-L1 inhibitors and VEGF-TKIs in combination or in sequence. Methods: Adults with histologically confirmed ccRCC and KPS score ≥70% are eligible. Patients in substudy 03A cannot have previously received systemic therapy for advanced ccRCC. Patients in substudy 03B must have progression (per RECIST v1.1) on or after treatment with a PD-1/PD-L1 inhibitor and a VEGF-TKI for advanced ccRCC. Both substudies will have a safety lead-in phase for experimental combinations with investigational agents to establish a recommended phase 2 dose, followed by an efficacy phase. Experimental arms will enroll approximately 80 (03A) and 50 (03B) patients. Patients will be randomly assigned 2:1 (03A) or 1:1 (03B) to an experimental arm or a reference arm (pembrolizumab 400 mg IV every 6 weeks [Q6W] + lenvatinib 20 mg orally once daily [QD]). Experimental arms in 03A are MK-1308A (coformulation of quavonlimab 25 mg and pembrolizumab 400 mg IV Q6W) + lenvatinib (20 mg orally QD), MK-4280A (coformulation of favezelimab 800 mg and pembrolizumab 200 mg IV every 3 weeks [Q3W]) + lenvatinib (20 mg orally QD), and belzutifan (120 mg orally QD) + lenvatinib (20 mg orally QD) + pembrolizumab (400 mg Q6W IV). Experimental arms in 03B are MK-1308A, MK-4280A, pembrolizumab (400 mg Q6W IV) + belzutifan (120 mg orally QD), lenvatinib (20 mg orally QD) + belzutifan (120 mg orally QD), and pembrolizumab (200 mg IV Q3W) + MK-4830 (800 mg IV Q3W). Treatment will continue until disease progression, unacceptable toxicity, or withdrawal of consent. Primary end points for the safety lead-in phase are safety and tolerability; coprimary end points for the efficacy phase are safety and objective response rate per RECIST v1.1 by blinded independent central review (BICR). Secondary end points during the efficacy phase are duration of response, progression-free survival (RECIST v1.1 by BICR), clinical benefit rate, and overall survival. Both substudies are recruiting patients in Australia, Canada, France, Israel, South Korea, Spain, New Zealand, the United Kingdom, and the United States. Clinical trial information: NCT04626479; NCT04626518.

Active surveillance in metastatic renal cell carcinoma: A single-center cohort

389

Background: Emerging data suggest that active surveillance (AS) may be safely implemented in a subset of patients (pts) with metastatic renal cell carcinoma (RCC) and indolent disease to delay the initiation of systemic therapy without undermining long-term survival. However, widespread adoption of AS has been limited by a lack of data on factors portending favorable outcomes. In this study we sought to characterize pts undergoing AS at a large academic medical center to identify factors associated with time on AS. Methods: We identified pts on AS using Kidney Cancer Explorer (KCE), the data management platform of the Kidney Cancer Program at UT Southwestern Medical Center (2005-2020), as well as input from medical oncologists. The AS cohort was defined by (1) having metastatic RCC (determined by either a suspicious lesion > 1cm or a positive biopsy), and (2) the absence of prior systemic therapy. Baseline characteristics and IMDC criteria were evaluated at the outset. Outcomes of interest included progression free survival (PFS), time to systemic therapy (TST), and overall survival (OS). Survival estimates were generated using Kaplan Meier methods. Cox proportional hazard models were used in univariate and multivariate analyses to identify baseline characteristics associated with TST. Results: We identified 37 pts with metastatic RCC undergoing AS; 31 pts (83.8%) had ccRCC, 28 pts (75.7%) had a favorable IMDC prognostic group, 18 pts (48.6%) had one metastatic lesion at baseline, and the cohort had an average tumor burden of 21mm. The majority of pts had clinical or radiologic progression with a median PFS of 10.8 months (95% CI: 8.13-23.31). The median TST was 37 months (95% CI: 24.3-94.9). In total, there were 11 deaths (none of which occurred prior to the initiation of systemic therapy) and median OS after the initiation of AS was 132.5 months (95% CI: 87.3-NR). Multivariate analyses showed that higher numbers of metastatic lesions at baseline were associated with a shorter TST (HR:1.45; 95% CI: 1.03-2.03, p = 0.03). At a median follow-up of 62.5 months, 11/37 (29%) of pts had not yet started systemic therapy. Conclusions: These results expand upon previous studies and support a role for AS to delay systemic therapy in selected pts with metastatic RCC.

Phase II study of nivolumab and salvage nivolumab + ipilimumab in treatment-naïve patients (pts) with advanced clear cell renal cell (HCRN GU16-260-Cohort A): Final report

288

Background: Nivolumab (nivo) is FDA approved for patients (pts) with VEGFR TKI-resistant RCC and the nivo + ipilimumab (nivo/ipi) combination is FDA approved for treatment naïve pts with IMDC intermediate and poor risk renal cell carcinoma (RCC). Little information was available on the efficacy and toxicity of nivo monotherapy in treatment naïve RCC or the efficacy of nivo/ipi salvage in pts with tumors resistant to initial nivo monotherapy. Methods: Eligible pts with treatment naïve RCC received nivo 240mg IV q2 wk x 6 doses followed by 360mg IV q3 wk x 4 doses followed by 480 mg q4 wk until progressive disease (PD), toxicity, or completion of 96 wks of treatment (Part A). Pts with PD prior to, or stable disease (SD) at 48 wks (pSD) were potentially eligible to receive salvage nivo (3mg/kg)/ipi (1 mg/kg) q3 wk x 4 doses followed by q4 wk nivo maintenance for up to 48 wks (Part B). All pts were required to submit tissue from a metastatic lesion obtained within 12 months (mos) prior to study entry and prior to Part B for correlative studies. Results: 123 pts with clear cell(cc) RCC were enrolled between 5/2017 and 12/2019 at 12 participating HCRN sites. Data lock was 04/07/2021. Median Follow-up 26.9 mos. Median age 65 (32-86) years; 72% male. IMDC risk: favorable (Fav) 35 (28%), intermediate (I) 76 (62%) and poor (P) 12 (10%). 22 (18%) had a component of sarcomatoid histology (SARC). RECIST defined ORR was: 34.1% (25.8-43.2%) (CR 6.5%, PR 27.6%), SD 47 (35.8%). ORR by irRECIST was 39%. ORR by IMDC was: Fav 20/35 (57.1%) (39-74%), (I/P) 22/88 (25%) and for SARC 36.4%. ORR by PD-L1 status was 21/78 (27%), 8/16 (50%) and 6/8 (75%) for pts with tumor PD-L1 of 0, 1-20 or > 20%, respectively (trend test p-value 0.002). 5/7 (71.4%) Fav pts with PD-L1 > 1 responded. Median DOR was 27.6 (13.7, NA) mos with 26/42 responders including 17/20 (85%) with Fav Risk remaining progression free. Median PFS was 8.2 (5.5, 10.9) mos; (30.3 for IMDC Fav and 5.4 for I/P). 91 pts remain alive with 24 mos OS rate of 78%. 65 patients (59 PD, 6 pSD) were potentially eligible for salvage nivo/ipi (Part B), but 25 did not enroll due to symptomatic PD (6), grade 3-4 toxicity on nivo (17), or other (2) and 5 were not treated due to inability to confirm residual disease on a biopsy. ORR for Part B by RECIST was 11.4% (4/35) and by irRECIST 17.2%. Grade 3-5 treatment-related AEs (TrAE) (not including asymptomatic amylase/lipase) were seen in 20.3% in Part A and 14.2% in Part B with 1 death in each cohort. Conclusions: Nivo monotherapy is active in treatment naïve ccRCC across all IMDC groups. Although efficacy appears less than combination nivo/ipi in I/P pts, Fav pts had a notably high ORR and DOR. Efficacy appeared to correlate with tumor PD-L1 status, although at least half the responders had a tumor PD-L1 of 0. Salvage treatment with nivo/ipi after nivo was frequently not feasible and of limited benefit. Clinical trial information: NCT03117309.

Molecular alterations across sites of metastasis in patients with renal cell carcinoma (RCC)

287

Background: RCC has a distinct pattern of metastatic spread with common sites of metastasis including the lung, bone, and liver. Less common sites include the brain, adrenal gland, and pancreas. While the pattern of metastatic spread has prognostic significance, the biology driving tropism to specific organ sites has not been fully characterized. We utilized a multi-institutional real-world dataset to examine genomic alterations and transcriptional signatures across the spectrum of metastatic sites in patients with RCC. Methods: RCC tissue specimens derived from the kidney and distant metastatic sites were sequenced utilizing a commercially available Clinical Laboratory Improvement Amendments (CLIA)-certified assay by Caris Life Sciences. Whole exome and transcriptome sequencing was performed. Molecular subgroups were defined according to the IMmotion151 metastatic RCC subtypes, with subgroups determined by a weighted average of gene expression levels. Molecular analysis and PD-L1 expression (SP142) were described by metastasis site. Results: 657 RCC samples from 653 patients underwent molecular profiling. The median age was 62 years (range 14-90) and the majority were male (70.6%). The most common histology was clear cell RCC (n = 509, 77.5%), followed by papillary (n = 63, 9.6%), chromophobe (n = 30, 4.6%), medullary (n = 8, 1.2%), collecting duct (n = 6, 0.9%), and mixed (n = 41, 6.2%). Specimen source included the kidney (n = 340, 51.8%), lung (n = 75, 11.4%), bone (n = 45, 6.8%), lymph nodes (n = 34, 5.2%), liver (n = 28, 4.3%), endocrine glands (adrenal, pancreas, and thyroid; n = 23, 3.5%), brain/CNS (n = 16, 2.4%), and other metastatic sites (n = 96, 14.6%). Compared to kidney, several genes were mutated at higher rates for select metastatic sites, including PBRM1 (59.5% bone, 59.1% endocrine, and 45.9% lung vs 33.8% kidney, p< 0.05) and KDM5C (27.8% endocrine, 29.2% lymph nodes, and 35.3% soft tissue vs 9.3% kidney, p< 0.05). When evaluating metastatic specimens versus kidney specimens, bone metastases had a significantly higher proportion of tumors classified as ‘Angio/stromal’ (n = 19, 42.2%; vs n = 52, 15.4%; p< 0.0001), while liver metastases had a higher proportion of the ‘complement/Ω-oxidation’ subgroup (n = 17, 60.7%; vs n = 48, 14.1%; p< 0.0001). PD-L1 expression in metastatic sites (range 6.8%-21.7%, with exception of 0% in GI; p= 0.09 to 0.99) was not significantly different from the kidney (16.6%). Conclusions: In our contemporary real-world analysis, we demonstrate differential patterns of molecular alterations among sites of metastasis in RCC. Our observations elucidate the biology underlying heterogeneous disease outcomes associated with site of metastasis. Application of predictive signatures by site of metastasis may help inform personalized therapy strategies in advanced RCC. Further studies are warranted to validate our findings.

PIVOT IO 011: A phase 1/2 study of bempegaldesleukin (BEMPEG; NKTR-214) plus nivolumab (NIVO) and tyrosine kinase inhibitor (TKI) versus NIVO and TKI alone in patients (pts) with previously untreated advanced or metastatic renal cell carcinoma (mRCC)

TPS403

Background: The current standard of care for advanced RCC (aRCC) utilizes immune checkpoint inhibitors (ICIs) and targeted agents. Novel combinations of these agents, such as NIVO + TKIs, have demonstrated clinical benefit over TKI monotherapy. In CheckMate 9ER, NIVO + cabozantinib (CABO) in aRCC demonstrated clinically meaningful efficacy results and a favorable safety profile, and was FDA approved (01/2021). High-dose interleukin-2 (IL-2) was used historically for durable responses in mRCC but had unfavorable toxicity with complex inpatient treatment regimens. BEMPEG, an immunostimulatory IL-2 cytokine prodrug, is engineered to deliver a controlled, sustained, and preferential signal to the clinically validated IL-2 pathway. Preferential binding of BEMPEG to the IL-2 heterodimeric receptor (IL-2Rβγ) activates and expands CD8+ T cells and NK cells over immunosuppressive Tregs. In the phase 1/2 PIVOT-02 study, BEMPEG + NIVO displayed encouraging antitumor activity in pts with mRCC, with a tolerable safety profile. The clinical activity and the manageable, non-overlapping toxicity profiles of the individual agents in this combination warrants exploration of triplet regimens in previously untreated aRCC. Methods: PIVOT IO 011 (NCT04540705) is a 2-part, phase 1/2, randomized, open-label study assessing the safety and efficacy of BEMPEG + NIVO + TKI triplet in pts with untreated aRCC or mRCC. In Part 1, pts will receive BEMPEG + NIVO + TKI (Part 1A: axitinib [AXI] or Part 1B: CABO; n≈6–24 pts in each TKI arm). While BEMPEG + NIVO dosing will remain consistent across phases, each TKI will have 2 doses evaluated in Part 1, and results will determine the recommended phase 2 dose for AXI/CABO in Part 2. In Part 2, pts will be randomized 1:1 to receive either BEMPEG + NIVO + CABO or NIVO + CABO (N≈250), stratified by IMDC prognostic score and prior nephrectomy status. If the CABO triplet has an unacceptable toxicity profile, Part 2 may be amended to use the AXI triplet. Key inclusion criteria: aRCC or mRCC with clear cell component; no prior systemic therapy for RCC, except 1 prior adjuvant/neoadjuvant therapy for completely resectable RCC (must have included an anti–VEGF agent with recurrence ≥6 months after last dose); and Karnofsky PS ≥70%. Key exclusion criteria: active CNS brain/leptomeningeal metastases; active, known, or suspected autoimmune disease; and inadequately treated adrenal insufficiency. Primary endpoints in Part 1: dose-limiting toxicities and safety; and in Part 2: overall response rate per RECIST v1.1 by investigator. Secondary endpoints in Part 2: progression-free survival, overall survival, safety. Duration of BEMPEG + NIVO will be ≤2 years, and treatment with TKI will continue until disease progression. The study is currently recruiting. Clinical trial information: NCT04540705.

Neoadjuvant Nivolumab in Patients with High-risk Nonmetastatic Renal Cell Carcinoma

Neoadjuvant immune checkpoint blockade represents a novel approach for potentially decreasing the risk of recurrence in patients with nonmetastatic renal cell carcinoma (RCC). In this early phase clincal tiral, we evaluated the safety and tolerability of neoadjuvant treatment with the programmed cell death protein 1 (PD-1) inhibitor nivolumab in patients with nonmetastatic high-risk RCC. Nonprimary endpoints included objective radiographic tumor response rate, immune-related pathologic response rate, quality of life alterations, and metastasis-free and overall survival. In total, 17 patients were enrolled in this study and underwent surgery without a delay after receiving three every-2-wk doses of neoadjuvant nivolumab. Adverse events (AEs) of any grade occurred in 14 (82.4%) patients, with two (11.8%) experiencing grade 3 events. Ten (58.8%) patients experienced an AE of any grade potentially attributable to nivolumab (all grade 1-2), and no grade 4-5 AEs occurred regardless of treatment attribution. The most common AEs were grade 1 fatigue (41.2%), grade 1 pruritis (29.4%), and grade 1 rash (29.4%). All evaluable patients had stable disease as per established radiographic criteria, with one (6.7%) demonstrating features of an immune-related pathologic response. Quality of life remained stable during treatment, with improvements relative to baseline noted at ≥6 mo postoperatively. Metastasis-free survival and overall survival were 85.1% and 100% at 2 yr, respectively. PATIENT SUMMARY: In this study, we evaluated the safety and tolerability of preoperative administration of three doses of the immune checkpoint inhibitor nivolumab in patients with clinically localized high-risk renal cell carcinoma. We demonstrated the safety of this approach and found that, although most patients will not experience a radiographic response to treatment, a subset may have features of an immune-related pathologic response.

Treatment-free Survival after Immune Checkpoint Inhibitor Therapy versus Targeted Therapy for Advanced Renal Cell Carcinoma: 42-Month Results of the CheckMate 214 Trial

PURPOSE

Patients discontinuing immuno-oncology regimens may experience periods of disease control without need for ongoing anticancer therapy, but toxicity may persist. We describe treatment-free survival (TFS), with and without toxicity.

PATIENTS AND METHODS

Data were analyzed from the randomized phase III CheckMate 214 trial of nivolumab plus ipilimumab (n = 550) versus sunitinib (n = 546) for treatment-naïve, advanced renal cell carcinoma (aRCC). TFS was estimated by the 42-month restricted mean times defined by the area between Kaplan-Meier curves for two time-to-event endpoints defined from randomization: time to protocol therapy cessation and time to subsequent systemic therapy initiation or death. TFS was subdivided as TFS with and without toxicity by counting days with ≥1 grade ≥3 treatment-related adverse event (TRAE).

RESULTS

At 42 months since randomization, 52% of nivolumab plus ipilimumab and 39% of sunitinib intermediate/poor-risk patients were alive; 18% and 5% surviving treatment-free, respectively. Among favorable-risk patients, 70% and 73% of nivolumab plus ipilimumab and sunitinib patients were alive; 20% and 9% treatment-free. Over the 42-month period, mean TFS was over twice as long after nivolumab plus ipilimumab than sunitinib for intermediate/poor-risk (6.9 vs. 3.1 months) and three times as long for favorable-risk patients (11.0 vs. 3.7 months). Mean TFS with grade ≥3 TRAEs was a small proportion of time for both treatments (0.6 vs. 0.3 months after nivolumab plus ipilimumab vs. sunitinib for intermediate/poor-risk, and 0.9 vs. 0.3 months for favorable-risk patients).

CONCLUSIONS

Patients initiating first-line nivolumab plus ipilimumab for aRCC spent more survival time treatment-free without toxicity versus those on sunitinib, regardless of risk group.

A Prospective Multicenter Evaluation of Initial Treatment Choice in Metastatic Renal Cell Carcinoma Prior to the Immunotherapy Era: The MaRCC Registry Experience

INTRODUCTION

The Metastatic Renal Cell Carcinoma (MaRCC) Registry provides prospective data on real-world treatment patterns and outcomes in patients with metastatic renal cell carcinoma (mRCC).

METHODS AND MATERIALS

Patients with mRCC and no prior systemic therapy were enrolled at academic and community sites. End of study data collection was in March 2019. Outcomes included overall survival (OS). A survey of treating physicians assessed reasons for treatment initiations and discontinuations.

RESULTS

Overall, 376 patients with mRCC initiated first-line therapy; 171 (45.5%) received pazopanib, 75 (19.9%) sunitinib, and 74 (19.7%) participated in a clinical trial. Median (95% confidence interval) OS was longest in the clinical trial group (50.3 [35.8-not reached] months) versus pazopanib (39.0 [29.7-50.9] months) and sunitinib 26.2 [19.9-61.5] months). Non-clear cell RCC (21.5% of patients) was associated with worse median OS than clear cell RCC (18.0 vs. 47.3 months). Differences in baseline characteristics, treatment starting dose, and relative dose exposure among treatment groups suggest selection bias. Survey results revealed a de-emphasis on quality of life, toxicity, and patient preference compared with efficacy in treatment selection.

CONCLUSION

The MaRCC Registry gives insights into real-world first-line treatment selection, outcomes, and physician rationale regarding initial treatment selection prior to the immunotherapy era. Differences in outcomes between clinical trial and off-study patients reflect the difficulty in translating trial results to real-world patients, and emphasize the need to broaden clinical trial eligibility. Physician emphasis on efficacy over quality of life and toxicity suggests more data and education are needed regarding these endpoints.

Active surveillance of metastatic renal cell carcinoma: Results from a prospective observational study (MaRCC)

BACKGROUND

Systemic therapy (ST) can be deferred in patients who have metastatic renal cell carcinoma (mRCC) and slow-growing metastases. Currently, this subset of patients managed with active surveillance (AS) is not well described in the literature.

METHODS

This was a prospective observational study of patients with mRCC across 46 US community and academic centers. The objective was to describe baseline characteristics and demographics of patients with mRCC initially managed by AS, reasons for AS, and patient outcomes. Descriptive statistics were used to characterize demographics, baseline characteristics, and patient-related outcomes. Wilcoxon 2-sample rank-sum tests and χ² tests were used to assess differences between ST and AS cohorts in continuous and categorical variables, respectively. Kaplan-Meier survival curves were used to assess survival.

RESULTS

Of 504 patients, mRCC was initially managed by AS (n = 143) or ST (n = 305); 56 patients were excluded from the analysis. Disease was present in 69% of patients who received AS, whereas the remaining 31% had no evidence of disease. At data cutoff, 72 of 143 patients (50%) in the AS cohort had not received ST. The median overall survival was not reached (95% CI, 122 months to not estimable) in patients who received AS versus 30 months (95% CI, 25-44 months) in those who received ST. Quality of life at baseline was significantly better in patients who were managed with AS versus ST.

CONCLUSIONS

AS occurs frequently (32%) in real-world clinical practice and appears to be a safe and appropriate alternative to immediate ST in selected patients.

Phase II study of nivolumab and salvage nivolumab + ipilimumab in treatment-naïve patients (pts) with advanced non-clear cell renal cell carcinoma (nccRCC) (HCRN GU16-260-Cohort B)

4510

Background: The HCRN GU16-260 trial reported on the efficacy and toxicity of nivo monotherapy in treatment naïve clear cell RCC (Cohort A) and the efficacy of nivo/ipi salvage therapy in pts with tumors resistant to initial nivo monotherapy (Atkins JCO 2020.38.15_suppl.5006). Limited information is available on the effects of such an approach in pts with advanced nccRCC. Methods: Eligible pts with treatment-naïve nccRCC received nivo 240mg IV q2 wk x 6 doses followed by 360mg IV q3 wk x 4 doses followed by 480 mg q4 wk until progressive disease (PD), toxicity, or completion of 96 wks of treatment (Part A). Pts with PD prior to or stable disease (SD) at 48 wks (pSD) were potentially eligible to receive salvage nivo (3mg/kg) /ipi (1 mg/kg) q3 wk x 4 doses followed by q4 wk nivo maintenance for up to 48 wks (Part B). All pts were required to submit tissue from a metastatic lesion obtained within 12 months (mo) prior to study entry and prior to enrolling on Part B for correlative studies. Results: 35 pts with nccRCC were enrolled between 5/2017 and 12/2019 at 12 participating HCRN sites. Median age 63 (range 35-84 years); 89% male. IMDC favorable 8 (23%), intermediate 18 (51%) and poor risk 9 (26%). Of the 35 pts 19 (54%) had papillary, 6 (17%) chromophobe and 10 (29%) unclassified histology. RECIST defined ORR was 5 of 35 (14.3%) [CR 2 (5.7%), PR 3 (8.6%)], SD 16 (45.7%), PD 14 (40.0%). Immune-related ORR was 8 of 35 (22.9%). RECIST ORR by histology was: papillary - 1/19 (5%); chromophobe - 1/6 (17%); unclassified - 3/10 (30%). 9 pts (26%) had tumors with sarcomatoid features with 3 (33%) (2 unclassified, 1 papillary) responding. Median PFS was 4.0 (2.7, 4.3) mo. 21 pts remain alive. None of the responders have progressed or died. 28 pts (25 PD, 3 pSD) were potentially eligible for salvage nivo/ipi (Part B), but 12 did not enroll due to symptomatic PD (2), grade 3-4 toxicity on nivo (3), or other including no biopsy tissue (7). In the 16 Part B pts, best response to nivo/ipi was: PR (1, 6%) – (unclassified/non-sarcomatoid); SD (7, 44%); PD (8, 50%). Grade 3 Treatment-related adverse events (TrAEs) were seen in 7/35 (20%) on nivo. Grade 3-5 TrAEs were seen in 7/16 (44%) on nivo/ipi with 1 pt experiencing sudden death. Correlative studies including PD-L1 status, WES and RNAseq are pending. Conclusions: Nivo monotherapy has limited activity in treatment naïve nccRCC with most responses (4 of 5) seen in pts with sarcomatoid and/or unclassified tumors. Toxicity is consistent with prior nivo studies. Salvage treatment with nivo/ipi was provided in 16 of 28 (57%) pts with PD/pSD on nivo monotherapy, with 1 response observed. Clinical trial information: NCT03117309.

A phase 1b/2 umbrella study of investigational immune and targeted combination therapies as first-line therapy for patients with advanced renal cell carcinoma (RCC)

TPS4594

Background: For advanced clear cell RCC (ccRCC), first-line treatment with PD-1/PD-L1 inhibitors in combination with CTLA-4 inhibitors or VEGF TKIs are established treatment options. However, patients eventually experience progression; therefore, more effective therapies are needed. This umbrella platform study is an open-label, rolling-arm, multicenter, phase 1b/2 trial with an adaptive design that will evaluate the safety and efficacy of experimental combinations of investigational agents in advanced ccRCC based on their mechanisms of action and toxicity profile. Substudy 03A (NCT04626479) will evaluate treatment combinations as first-line therapy for patients with advanced ccRCC. Given promising results of the phase 1b/2 KEYNOTE-146 (NCT02501096) and phase 3 KEYNOTE-581/CLEAR (NCT02811861) studies, pembrolizumab (400 mg IV Q6W) + lenvatinib (20 mg orally QD) will be used as the reference arm. Methods: Patients must be aged ≥18 years with histologically confirmed ccRCC, measurable disease per RECIST v1.1, and KPS score ≥70 and must have not received prior systemic therapy for advanced RCC (neoadjuvant therapy is acceptable if completed ≥12 mo before randomization). The study will comprise a safety lead-in phase for experimental combinations with investigational agents without an established recommended phase 2 dose (RP2D) and an efficacy phase. Patients will be randomly assigned 2:1 to an experimental arm or a reference arm. Each experimental arm will contain approximately 80 patients. During the efficacy phase, if more than 1 experimental arm is open for enrollment, patients in the reference arm can be shared. Treatments in the experimental arms are composed of the following: MK-1308A (coformulation of quavonlimab [MK-1308] 25 mg + pembrolizumab 400 mg IV Q6W) + lenvatinib (20 mg orally QD), MK-4280A (coformulation of MK-4280 800 mg + pembrolizumab 200 mg IV Q3W) + lenvatinib (20 mg orally QD), and pembrolizumab (400 mg Q6W IV) + belzutifan (MK-6482, 120 mg orally QD) + lenvatinib (20 mg orally QD). Treatment with pembrolizumab (including coformulations with MK-1308 and MK-4280) will continue up to 2 years, whereas treatment with lenvatinib and belzutifan will continue until disease progression, unacceptable toxicity, or withdrawal of consent. Patients will be stratified by IMDC risk group (favorable vs intermediate/poor). Tumor imaging will occur 12 weeks after randomization, then Q6W until week 54, and Q12W thereafter. Coprimary end points are safety and tolerability, establishing the RP2D during the safety lead-in phase (if applicable) and objective response rate per RECIST v1.1 by blinded independent central review (BICR) during the efficacy phase. Secondary end points during the efficacy phase are duration of response, progression-free survival and clinical benefit rate per RECIST v1.1 (BICR), and overall survival. Clinical trial information: NCT04626479.

Phase II trial of stereotactic ablative radiation (SAbR) for oligoprogressive kidney cancer

4564

Background: Metastatic renal cell carcinoma (mRCC) patients on systemic therapy may experience oligoprogression. SAbR has been demonstrated to be safe and is associated with high local control rates in mRCC. In this prospective phase II single arm trial, we investigated SAbR to control oligoprogressive mRCC. Methods: Patients with mRCC who demonstrated response to systemic therapy with subsequent radiographic evidence of three or fewer sites of progression were treated with SAbR to all progressive sites. Systemic therapy was held during SAbR at the discretion of the treating oncologist. Follow-up included radiographic imaging at three-month intervals. Sequential SAbR for continued oligoprogression was allowed. The primary objective was extension of ongoing systemic therapy by >6 months in 40% of the patients. Progression was defined by any of these 3 criteria: (1) local failure at a radiated site; (2) progression ineligible for additional SAbR (>3 sites) or involving >30% of metastasis; or (3) progression as clinically determined by treating physicians. An exact binomial test was used to test the probability of postponing systemic therapy. Secondary endpoints focused on overall survival (OS), local control (LC) rates, toxicity, and health-related quality of life (QOL). Results: The trial completed accrual with enrollment of 20 patients who received SAbR to a total of 36 sites. At enrollment four, twelve, three, and one patients were on first, second, third, and fourth line of systemic therapy, respectively. Eleven were on immunotherapy and nine on a tyrosine-kinase inhibitor. Three patients required repeat SAbR to a new site for sequential disease control. At a median follow-up of 8.3 months (interquartile range 3.9 – 15.1), SAbR extended the duration of the ongoing systemic therapy by >6 months in 12 out of 17 patients (70.6%, 95% CI: 48.9%-92.3%). Thirteen out of 20 patients progressed with a median PFS of 8.7 months (95% CI: 3.2-12.4). Five patients died and the OS did not reach the median. LC was 36/36 (100%). Treatment related grade 1 and grade 2 toxicity was experienced by three and one patient, respectively; no grade 3 toxicities were reported. When compared to baseline, no significant decline in QOL was detected. Conclusions: SAbR extended PFS of ongoing systemic by >6 months in oligoprogressive patients with mRCC. SAbR was safe and did not adversely affect QOL. These data support further evaluation of SAbR for oligoproressive mRCC in a prospective randomized setting. Clinical trial information: NCT03696277.

Association of chronic use of proton pump inhibitors with an increased risk of immune checkpoint inhibitor-induced colitis in renal cell carcinoma

e16550

Background: Immune checkpoint inhibitors (ICI) have become standard of care in metastatic renal cell carcinoma (mRCC) but are associated with immune-related adverse events (irAEs) including immune-related colitis (irC). Growing evidence suggests that proton pump inhibitors (PPIs) are associated with an increased risk of inflammatory bowel disease (IBD). Given the pathophysiological overlap between IBD and irC, we sought to evaluate the relationship between PPI use and irC in mRCC patients. Methods: We performed a retrospective study of adult patients who received ICI for mRCC between 2015 and 2018 at two tertiary care centers. Clinical characteristics, oncological outcomes, irC details, and PPI use were collected by manual chart review. The diagnosis of irC was made via biopsy when available, or when unavailable (or inconclusive) by clinical criteria. Univariable and multivariable logistic regression analyses were conducted to assess PPI use and other potential risk factors of irC. Results: A total of 176 patients received immunotherapy for mRCC, of which 16 (9.1%) were diagnosed with irC. There were no significant differences between patients with and without irC in age, gender, medical comorbidities, RCC subtype, treatment history, and overall survival. However, Caucasian race, exposure to ipilimumab, and PPI use were more frequently observed in patients with irC than those without. Patients with irC presented with elevated stool lactoferrin and calprotectin and a wide range of endoscopic and histologic findings. In univariable and multivariable logistic regression analyses, Caucasian race, exposure to ipilimumab and chronic use of PPIs >8 weeks were significantly associated with irC (Table). Conclusions: PPI use may be a modifiable risk factor for irC development in patients with mRCC.[Table: see text]

Cabozantinib (C) in combination with nivolumab (N) and ipilimumab (I) (CaNI) for advanced renal cell carcinoma with variant histology (aRCCVH)

TPS4592

Background: Despite advances in therapy of clear cell renal cell carcinoma, outcomes for patients with aRCCVH remain poor and these patients have typically been excluded from pivotal phase III studies. COSMIC-313 (NCT03937219) exploring C/N/I vs N/I excludes those with aRCCVH. Given responses seen with C as well as N/I in aRCCVH, there is reason to explore this triplet combination in this population. Methods: NCT04413123 is single arm phase 2 trial multi-institutional study involving Dana-Farber Cancer Institute, Beth Israel Deaconess Medical Center, Winship Cancer Institute, Karmanos Cancer Center, University of California in San Diego and University of Texas Southwestern. The primary objective is to assess the objective response rate (ORR) by investigator-assessed Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1 of C in combination with N/I in aRCCVH. Key secondary endpoints are progression-free survival (PFS), overall survival (OS) and toxicity by Common Terminology Criteria for Adverse Events (CTCAE) version 5. Mandatory pretreatment biopsy (unless medically infeasible) is required for correlative analysis to define the composition and transcriptional states of tumor and immune cells within the aRCCVH microenvironment in addition to determining the number and state of tumor-infiltrating T cell clones in aRCCVH and relation to response. Any variant histology is allowed, including clear-cell RCC with over 80% sarcomatoid features. Patients may be treatment naïve or received prior therapy including up to one anti-vascular endothelial growth factor agent not including C; prior therapy with immune checkpoint inhibitors is exclusionary. All International Metastatic RCC Database Consortium risk classifications are allowed; patients should have adequate organ function with performance status 0-1. C will be administered at a starting dose of 40 mg daily. N will be dosed at 3 mg/kg with I 1 mg/kg every 3 weeks followed by maintenance N 480 mg IV every 4 weeks and will be continued until progressive disease or unacceptable toxicity. C can be reduced to. 20 mg daily or 20 mg every other day as needed for toxicity. Dose reductions of N or I are not permitted but delays up to 12 weeks are allowed; N may be continued without I if toxicity can be directly attributed to I. Radiographic imaging is performed at baseline with first scheduled assessment at 12 weeks then every 8 weeks thereafter. A one-stage design is employed to enroll 40 eligible patients, which provides 93% power at 1-sided alpha of 0.09 to distinguish an ORR of 40% versus 20%. 12 or more responses are required to deem treatment promising. Seven of the planned 40 patients have been enrolled as of 2/1/2021. Clinical trial information: NCT04413123.

Angiogenic and T-effector subgroups identified by gene expression profiling (GEP) and propensity for PBRM1 and BAP1 alterations in clear cell renal cell carcinoma (ccRCC)

343

Background: With the emergence of multiple active treatment options in RCC, predictive biomarkers for optimal treatment selection are lacking. Gene expression data from IMmotion151 and Javelin Renal 101 clinical trials generated anti-angiogenic and immune signatures that warrant further validation. We aimed to describe the genomic and gene expression profiles in a multi-institutional database of patients with ccRCC, and its association with other biomarkers of interest. Methods: Whole transcriptome sequencing was performed for ccRCC patient samples submitted to a commercial CLIA-certified laboratory (Caris Life Sciences, Phoenix, AZ) from February 2019 to September 2020. Tumor GEP and hierarchical clustering based on the validated 66-gene signature (D’Costa et al, 2020) were used to identify patient subgroups. Samples from both primary tumors and metastatic sites were included. Results: A total of 316 patients with ccRCC, median age 62 (range 32-90), 71.8% men, were included. Tissue samples were obtained from primary tumor (46.5%), lung (12.3%), bone (9.5%), liver (4.7%) and other metastatic sites (27%). Gene expression analysis identified angiogenic, mixed and T-effector subgroups in 24.1%, 51.3% and 24.7%, respectively. Patients with angiogenic subgroup tumors compared to those with T-effector subgroup tumors were more likely to be older (63 versus 60 years, p=0.035), female (40.8% versus 16.7%, p=0.0009) and more frequently found in pancreatic/small bowel metastases (75% versus 12.5%, p=0.0103). Biomarkers of potential response to immunotherapy such as PD-L1 (p=0.0021), TMB (not significant), and dMMR/MSI-H status (not significant) were more frequent in the T-effector subgroup. PBRM1 mutations were more common in the angiogenic subgroup (62.0% vs 37.5%, p=0.0034) while BAP1 mutations were more common in the T-effector subgroup (18.6% versus 3.0%, p= 0.0035). Immune cell population abundance (e.g. NK cells, monocytes) and immune checkpoint gene expression (TIM-3, PD-L1, PD-L2, CTLA4) were also increased in the T-effector subgroup. Conclusions: Our hierarchical clustering results based on the 66-gene expression signature were concordant with results from prior studies. Patient subgroups identified by evaluation of angiogenic and T-effector signature scores exhibit significantly different mutations and immune profiles. These findings require prospective validation in future biomarker-selected clinical trials.

Patterns of progression in patients treated with nivolumab plus ipilimumab (NIVO+IPI) versus sunitinib (SUN) for first-line treatment of advanced renal cell carcinoma (aRCC) in CheckMate 214

313

Background: First-line NIVO+IPI demonstrates superior survival and response benefits in intent-to-treat (ITT) patients (pts) with aRCC after long-term follow-up in the phase 3 CheckMate 214 trial. Data are scarce on tumor relapse and patterns of disease progression with immuno-oncology agents in this setting. This exploratory analysis of CheckMate 214 characterizes patterns of progression with NIVO+IPI vs SUN with 4 years minimum follow-up. Methods: Pts with clear cell aRCC were randomized to NIVO+IPI Q3W×4 followed by NIVO monotherapy Q2W, or SUN QD×4 weeks (6-week cycle). Patterns of progression were characterized in ITT pts and analyzed post hoc using descriptive statistics. Progression patterns were defined by ≥ 20% target lesion growth (T), unequivocal progression of nontarget lesions (NT), and new lesion(s) (NL). Response and progression were assessed per independent radiology review committee via RECIST v1.1. Results: Radiographic progression (RP) was documented in 299/550 (54.4%) ITT pts with NIVO+IPI vs 289/546 (52.9%) with SUN. Among ITT pts with a confirmed response (objective response = 215/550 [39.1%, NIVO+IPI] vs 177/546 [32.4%, SUN]), 71/215 (33.0%) vs 84/177 (47.5%) pts experienced post-response RP with NIVO+IPI vs SUN; 8/59 (13.6%) vs 3/14 (21.4%) progressed after complete response, and 63/156 (40.4%) vs 81/163 (49.7%) progressed after partial response, respectively. The pattern of RP differed between arms (Table). With NIVO+IPI, 106/299 (35.5%) RPs resulted from NL only vs 74/289 (25.6%) with SUN, and this differential was more pronounced in pts with an initial confirmed response (36/71 [50.7%] vs 23/84 [27.4%]). Most NL-only RPs in initial responders occurred in a single organ (34/36 [94.4%] for NIVO+IPI; 20/23 [87.0%] for SUN) with the most common being lymph nodes (11/34 [32.4%]), brain (8/34 [23.5%]), and lung (5/34 [14.7%]) with NIVO+IPI, and lymph nodes (7/20 [35.0%]), brain (4/20 [20.0%]) and adrenal gland (3/20 [15.0%]) with SUN. Additional progression details, baseline characteristics, and key efficacy outcomes in progressors will be reported. Conclusions: Differential patterns of tumor relapse and disease progression were observed after long-term follow up of patients treated with NIVO+IPI vs SUN in CheckMate 214. NL-only progression occurred more often with NIVO+IPI vs SUN, in particular in the subset of pts who progressed post-response. These patterns may have therapeutic implications. Clinical trial information: NCT02231749 . [Table: see text]

Phase II trial of stereotactic ablative radiation (SAbR) for oligometastatic kidney cancer

311

Background: Stereotactic ablative radiotherapy (SAbR) is a promising treatment option for selected oligometastatic renal cell carcinoma (RCC) patients that can provide longitudinal disease control while preserving quality of life. Retrospective data have shown a local control (LC) rate greater than 90% and longitudinal disease control of over a year without systemic therapy. However, prospective validation of SAbR for oligometastatic RCC is lacking. In this prospective phase II single arm trial, we evaluated the impact of SAbR on freedom from systemic therapy (FFST). Methods: Treatment naïve patients with RCC confirmed by pathology and radiographic evidence of three or fewer extracranial metastases received SAbR with curative intent to all measurable sites of disease. Follow-up included radiographic imaging at three-month intervals to assess disease control. The primary endpoint was FFST defined as time from SAbR to the initiation of systemic therapy. Secondary endpoints included LC, modified progression-free survival (mPFS) (time from first SAbR to progression not amenable to further SAbR), PFS on subsequent systemic therapy, cancer-specific survival (CSS), overall survival (OS), toxicity and health-related quality of life (QOL) indices as measured with EQ-5D-5L and FACT-G. A Wilcoxon signed-rank test was used to evaluate the QOL indices. Results: The trial completed accrual with the enrollment of 23 patients who received SAbR to a total of 38 sites. At a median follow-up of 12 months (interquartile range 1.8-16), 1-year FFST was 87% (95% CI: 56%-96%). The 1-year mPFS was 79% (95% CI:49%-93%), while the median mPFS has not yet been reached. Three patients had disease progression at individual time points of 3.5, 4.0, and 12 months. One of these patients developed brain metastases that were controlled with gamma knife radiosurgery without initiating systemic therapy. The LC, CSS, and OS were 100% (38/38), 100% (23/23), and 95% (22/23), respectively. When compared to baseline, no significant decline in QOL was detected. Three patients experienced treatment-related grade 1 toxicity; no ≥grade 2 toxicities were reported. One patient died of an unrelated cause. Conclusions: SAbR is a safe and effective treatment for oligometastatic RCC that can provide longitudinal disease control and preserve quality of life. These data support further evaluation of SAbR for oligometastatic RCC in a randomized study. Clinical trial information: NCT02956798 .

Nivolumab versus everolimus in patients with advanced renal cell carcinoma: Updated results with long-term follow-up of the randomized, open-label, phase 3 CheckMate 025 trial

BACKGROUND

CheckMate 025 has shown superior efficacy for nivolumab over everolimus in patients with advanced renal cell carcinoma (aRCC) along with improved safety and tolerability. This analysis assesses the long-term clinical benefits of nivolumab versus everolimus.

METHODS

The randomized, open-label, phase 3 CheckMate 025 trial (NCT01668784) included patients with clear cell aRCC previously treated with 1 or 2 antiangiogenic regimens. Patients were randomized to nivolumab (3 mg/kg every 2 weeks) or everolimus (10 mg once a day) until progression or unacceptable toxicity. The primary endpoint was overall survival (OS). The secondary endpoints were the confirmed objective response rate (ORR), progression-free survival (PFS), safety, and health-related quality of life (HRQOL).

RESULTS

Eight hundred twenty-one patients were randomized to nivolumab (n = 410) or everolimus (n = 411); 803 patients were treated (406 with nivolumab and 397 with everolimus). With a minimum follow-up of 64 months (median, 72 months), nivolumab maintained an OS benefit in comparison with everolimus (median, 25.8 months [95% CI, 22.2-29.8 months] vs 19.7 months [95% CI, 17.6-22.1 months]; hazard ratio [HR], 0.73; 95% CI, 0.62-0.85) with 5-year OS probabilities of 26% and 18%, respectively. ORR was higher with nivolumab (94 of 410 [23%] vs 17 of 411 [4%]; P < .001). PFS also favored nivolumab (HR, 0.84; 95% CI, 0.72-0.99; P = .0331). The most common treatment-related adverse events of any grade were fatigue (34.7%) and pruritus (15.5%) with nivolumab and fatigue (34.5%) and stomatitis (29.5%) with everolimus. HRQOL improved from baseline with nivolumab but remained the same or deteriorated with everolimus.

CONCLUSIONS

The superior efficacy of nivolumab over everolimus is maintained after extended follow-up with no new safety signals, and this supports the long-term benefits of nivolumab monotherapy in patients with previously treated aRCC.

LAY SUMMARY

CheckMate 025 compared the effects of nivolumab (a novel immunotherapy) with those of everolimus (an older standard-of-care therapy) for the treatment of advanced kidney cancer in patients who had progressed on antiangiogenic therapy. After 5 years of study, nivolumab continues to be better than everolimus in extending the lives of patients, providing a long-lasting response to treatment, and improving quality of life with a manageable safety profile. The results demonstrate that the clinical benefits of nivolumab versus everolimus in previously treated patients with advanced kidney cancer continue in the long term.

Survival outcomes and independent response assessment with nivolumab plus ipilimumab versus sunitinib in patients with advanced renal cell carcinoma: 42-month follow-up of a randomized phase 3 clinical trial

BACKGROUND

The extent to which response and survival benefits with immunotherapy-based regimens persist informs optimal first-line treatment options. We provide long-term follow-up in patients with advanced renal cell carcinoma (aRCC) receiving first-line nivolumab plus ipilimumab (NIVO+IPI) versus sunitinib (SUN) in the phase 3 CheckMate 214 trial. Survival, response, and safety outcomes with NIVO+IPI versus SUN were assessed after a minimum of 42 months of follow-up.

METHODS

Patients with aRCC were enrolled from October 16, 2014, through February 23, 2016. Patients stratified by International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk and region were randomized to nivolumab (3 mg/kg) plus ipilimumab (1 mg/kg) every 3 weeks for four doses, followed by nivolumab (3 mg/kg) every 2 weeks; or SUN (50 mg) once per day for 4 weeks (6-week cycle). Primary endpoints: overall survival (OS), progression-free survival (PFS), and objective response rate (ORR) per independent radiology review committee in IMDC intermediate-risk/poor-risk patients. Secondary endpoints: OS, PFS, and ORR in the intention-to-treat (ITT) population and safety. Favorable-risk patient outcomes were exploratory.

RESULTS

Among ITT patients, 550 were randomized to NIVO+IPI (425 intermediate/poor risk; 125 favorable risk) and 546 to SUN (422 intermediate/poor risk; 124 favorable risk). Among intermediate-risk/poor-risk patients, OS (HR, 0.66; 95% CI, 0.55-0.80) and PFS (HR, 0.75; 95% CI, 0.62-0.90) benefits were observed, and ORR was higher (42.1% vs 26.3%) with NIVO+IPI versus SUN. In ITT patients, both OS benefits (HR, 0.72; 95% CI, 0.61-0.86) and higher ORR (39.1% vs 32.6%) were observed with NIVO+IPI versus SUN. In favorable-risk patients, HR for death was 1.19 (95% CI, 0.77-1.85) and ORR was 28.8% with NIVO+IPI versus 54.0% with SUN. Duration of response was longer (HR, 0.46-0.54), and more patients achieved complete response (10.1%-12.8% vs 1.4%-5.6%) with NIVO+IPI versus SUN regardless of risk group. The incidence of treatment-related adverse events was consistent with previous reports.

CONCLUSIONS

NIVO+IPI led to improved efficacy outcomes versus SUN in both intermediate-risk/poor-risk and ITT patients that were maintained through 42 months' minimum follow-up. A complete response rate >10% was achieved with NIVO+IPI regardless of risk category, with no new safety signals detected in either arm. These results support NIVO+IPI as a first-line treatment option with the potential for durable response.

TRIAL REGISTRATION NUMBER

NCT02231749.

Salvage Ipilimumab and Nivolumab in Patients With Metastatic Renal Cell Carcinoma After Prior Immune Checkpoint Inhibitors

PURPOSE

Immune checkpoint inhibitors (ICIs) are standard therapy in metastatic renal cell carcinoma (RCC). The safety and activity of the combination of ipilimumab and nivolumab in patients who have received prior ICI targeting the programmed death 1 (PD-1) pathway remains unknown. We evaluated ipilimumab and nivolumab in patients with metastatic RCC after prior treatment with anti-PD-1 pathway-targeted therapy.

PATIENTS AND METHODS

Patients with metastatic RCC who received prior anti-PD-1 pathway-targeted therapy and subsequently received ipilimumab and nivolumab were reviewed. Objective response rate and progression-free survival per investigator assessment were recorded. Toxicity of ipilimumab and nivolumab was also assessed.

RESULTS

Forty-five patients with metastatic RCC were included. All patients (100%) received prior ICIs targeting the PD-1 pathway. The median age was 62 years (range, 21-82 years). At a median follow-up of 12 months, the objective response rate to ipilimumab and nivolumab was 20%. The median progression-free survival while on ipilimumab and nivolumab was 4 months (range, 0.8-19 months). Immune-related adverse events (irAEs) of any grade with ipilimumab and nivolumab were recorded in 29 (64%) of the 45 patients; grade 3 irAEs were recorded in 6 (13%) of the 45 patients.

CONCLUSION

Ipilimumab and nivolumab demonstrated antitumor activity with acceptable toxicity in patients with metastatic RCC who had prior treatment with checkpoint inhibition.

Improved survival after cytoreductive nephrectomy for metastatic renal cell carcinoma in the contemporary immunotherapy era: An analysis of the National Cancer Database

OBJECTIVES

Despite immune checkpoint inhibitor (ICI) approval for metastatic renal cell carcinoma (mRCC) in 2015, cytoreductive nephrectomy (CN) is guided by extrapolation from earlier classes of therapy. We evaluated survival outcomes, timing, and safety of combining CN with modern immunotherapy (IO) for mRCC.

METHODS

From 96,329 renal cancer cases reported to the NCDB between 2015 and 2016, we analyzed 391 surgical candidates diagnosed with clear cell mRCC treated with IO ± CN and no other systemic therapies. Primary outcome was overall survival (OS) stratified by the performance of CN (CN + IO vs. IO alone). Secondary outcomes included OS stratified by the timing of CN, pathologic findings, and perioperative outcomes.

RESULTS

Of 391 patients, 221 (56.5%) received CN + IO and 170 (43.5%) received IO only. Across a median follow-up of 14.7 months, patients who underwent CN + IO had superior OS (median NR vs. 11.6 months; hazard ratio 0.23, P < 0.001), which was upheld on multivariable analyses. IO before CN resulted in lower pT stage, grade, tumor size, and lymphovascular invasion rates compared to upfront CN. Two of 20 patients (10%) undergoing CN post-IO achieved complete pathologic response in the primary tumor (pT0). There were no positive surgical margins, 30-day readmissions, or prolonged length of stay in patients undergoing delayed CN.

CONCLUSION

Using a large, national, registry-based cohort, we provide the first report of survival outcomes in mRCC patients treated with CN combined with modern IO. Our findings support an oncologic role for CN in the ICI era and provide preliminary evidence regarding the timing and safety of CN relative to IO administration.

Phase II study of nivolumab and salvage nivolumab + ipilimumab in treatment-naïve patients (pts) with advanced renal cell carcinoma (RCC) (HCRN GU16-260)

5006

Background: Nivolumab (nivo) is FDA approved for pts with VEGFR TKI-resistant RCC and the nivo + ipilimumab (nivo/ipi) combination is FDA approved for treatment naïve pts with IMDC intermediate and poor risk RCC. Little information is available on the efficacy and toxicity of nivo monotherapy in treatment naïve RCC or the efficacy of nivo/ipi salvage therapy in pts with tumors resistant to initial nivo monotherapy. Methods: Eligible pts with treatment naïve RCC received nivo 240mg IV q2 wk x 6 doses followed by 360mg IV q3 wk x 4 doses followed by 480 mg q4 wk until progressive disease (PD), toxicity, or completion of 96 wks of treatment (Part A). Pts with PD prior to or stable disease (SD) at 48 wks (pSD) were potentially eligible to receive salvage nivo (3mg/kg) /ipi (1 mg/kg) q3 wk x 4 doses followed by q4 wk nivo maintenance for up to 48 wks (Part B). All pts were required to submit tissue from a metastatic lesion obtained within 12 months (mo) prior to study entry and prior to Part B. Pathology specimens will be analyzed by immunohistochemistry, quantitative immunofluorescence, WES and RNAseq with results linked to clinical outcome. Results: 123 pts with clear cell(cc) RCC were enrolled between 5/2017 and 12/2019 at 12 participating HCRN sites. Median age 65 (range 32-86 years); 72% male. IMDC favorable 30 (25%), intermediate 79 (65%) and poor risk 12 (10%). 22 (18%) had a component of sarcomatoid histology (SARC). 117 pts are currently evaluable for response. RECIST defined ORR was: 34 (29.3%)[CR 5 (4.3%), PR 29 (24.8%)], SD 47 (40.2%), PD 36 (30.7%). ORR by irRECIST was 35%. ORR by IMDC was: favorable 12/29 (41.4%), intermediate/poor 22/87 (25.3%) and for SARC 6/22 (27.3%). Median DOR is 13.8 (10.9, NA) mo. Median PFS is 7.4 (5.5, 10.9) mo. 110 pts remain alive. 60 pts (54 PD, 6 pSD) to date were potentially eligible for salvage nivo/ipi (Part B), but 28 did not enroll due to symptomatic PD (17), grade 3-4 toxicity on nivo (8), other (3). 27 of 32 Part B pts are currently evaluable for efficacy and 30 for toxicity. Best response to nivo/ipi was PR (11%), SD (30%), PD (59%). ORR by irRECIST was 19%. Grade 3-5 Treatment-related AEs (TrAE) were seen in 35/123 (28)% on nivo with 1 death due to respiratory failure. Grade 3-4 TrAE were seen in 10/30 (33%) on nivo/ipi with 0 deaths. Correlative studies are pending. Conclusions: Nivo monotherapy is active in treatment naïve ccRCC across all IMDC groups. Toxicity is consistent with prior nivo studies. Salvage treatment with nivo/ipi after nivo monotherapy was feasible in 53% of pts with PD/pSD, with 11% responding. Clinical trial information: NCT03117309 .

Immune checkpoint inhibition-induced myocarditis in cancer patients: Proposal of a detection and management strategy

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Background: Monoclonal antibodies against the immune checkpoint inhibitors (ICI) programmed cell death protein-1 (PD-1), its ligand (PD-L1) and cytotoxic T-lymphocyte associated protein 4 (CTLA4) have had a transformative effect on the field of oncology. Autoimmune myocarditis (AIM) is a rare but potentially severe complication associated with these medications, without specific management guidelines. The aim of this observational report is to present four cases of AIM following ICI and propose a detection and treatment strategy. Methods: Four patients who received anti-PD-1 or anti-PD-L1 immune checkpoint inhibitors (ICI) developed severe cardiac manifestations within two weeks to several months after initiation. Demographic, historical, laboratory, and imaging data were collected by retrospective chart review. Results: Manifestations included LV systolic dysfunction, ventricular arrhythmias, and elevated cardiac enzymes. Myocardial ischemia was ruled out by coronary catheterization. Abnormal myocardial tissue characteristics on CMRI and biopsy were used to establish the diagnosis of myocarditis. Patients had endocrine, rheumatologic and neurologic irAEs (Table) and were managed by a multi-disciplinary team including oncology, rheumatology and cardiology. Management included prompt administration of high-dose steroids with rapid taper. Steroid sparing and escalation therapies included mycophenolate mofetil, methotrexate, rituximab, abatacept (CTLA4 agonist), as well as plasma exchange. This combination of tiered therapies resulted in substantial improvement in AIM. Conclusions: Clinical improvements seen in these cases highlight potential key elements for controlling autoimmune myocarditis response to ICI. We propose rapid diagnosis including CMRI and biopsy and initiation of high dose prednisone. We also recommend prompt initiation of steroid sparing agent within one month of diagnosis. Importantly, these patients should be managed by a multi-disciplinary team. [Table: see text]

Safety of weight-based dosing of nivolumab with or without ipilimumab by body mass index (BMI) stratified by sex across 14 CheckMate clinical trials

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Background: Associations between obesity and cancer risk, prognosis, and therapeutic outcomes have been extensively researched. However, the impact of BMI on safety in patients receiving immunotherapy has not been well described. Methods: A descriptive, retrospective analysis examined associations between BMI (kg/m2) (underweight/normal, BMI < 25; overweight, 25 ≤ BMI < 30; obese, BMI ≥ 30) and incidence of any-grade and grade 3/4 immune-mediated adverse events (imAEs) in patients receiving ≥ 1 dose of nivolumab 3 mg/kg as monotherapy (NIVO3; n = 2746). Data were pooled from CheckMate clinical trials across 8 tumor types. Data from nivolumab in combination with ipilimumab cohorts (n = 1026) and safety analyses by specific imAEs and tumor types will be presented. Results: Select NIVO3 monotherapy cohort patient demographics were: 68.5% male, median age of 61 years, median 10 doses received, and median BMI of 25.3 kg/m2. Results showed a trend towards higher incidence of any-grade, but not grade 3/4, imAEs in obese vs overweight and obese vs underweight/normal BMI patients (Table). BMI associations with imAE incidence were consistent with the overall trend across pre-defined subsets, including smoking status, age, and ECOG performance status. Both male and female patients had an increased incidence of any-grade imAEs with obesity; however, obese female patients had a higher incidence of grade 3/4 imAEs vs underweight/normal BMI (Table). Conclusions: This was a novel analysis of BMI and safety in 2746 patients across 8 tumor types in CheckMate clinical trials who were treated with nivolumab monotherapy. While obese patients showed a trend towards higher incidence of any-grade imAEs than those with overweight and underweight/normal BMI, incidence of grade 3/4 imAEs was consistent across BMI categories. Clinical trial information: CheckMate 017,026,057,025,039,205,040,066,067,141,275,142,016,214 (NCT numbers do not fit in field) . [Table: see text]

Summary From the First Kidney Cancer Research Summit, September 12-13, 2019: A Focus on Translational Research

Kidney cancer is one of the 10 most common cancers both in the United States and worldwide. Until this year, there had not previously been a conference focused on translational studies in the broad and heterogeneous group of kidney cancers. Therefore, a group of researchers, clinicians, and patient advocates dedicated to renal cell carcinoma launched the Kidney Cancer Research Summit (KCRS) to spur collaboration and further therapeutic advances in these tumors. This commentary aims to summarize the oral presentations and serve as a record for future iterations of this meeting. The KCRS sessions addressed the tumor microenvironment, novel methods of drug delivery, single cell sequencing strategies, novel immune checkpoint blockade and cellular therapies, predictive biomarkers, and rare variants of kidney cancers. In addition, the meeting included 2 sessions to promote scientific mentoring and kidney cancer research collaborations. A subsequent KCRS will be planned for the fall of 2020.

A real-world experience of immune checkpoint inhibitors (ICI) in metastatic renal cell carcinoma (mRCC)

647

Background: ICI therapy has changed the treatment landscape in mRCC. Here we present the safety and efficacy of ICIs used in an academic medical center (UT Southwestern Medical Center) and affiliated county hospital (Parkland Hospital). Methods: All mRCC patients (pts) treated with at least one dose of ICI from 2014 - 2018 were identified. Baseline characteristics were collected at the start of ICI. Outcomes included objective response rate (ORR) as determined by RECISCT v1.1, time to next treatment (TNT) and overall survival (OS). Immune-related adverse events (irAE) were graded according to CTCAE v4.0. Kaplan-Meier methods and Cox proportional hazards regression models were used to estimate survival and generate hazard ratios (HR). Results: We identified 177 pts with mRCC, including 31 at the county hospital, who received at least one dose of ICI. 140 (79.1%) pts were intermediate or poor risk by IMDC, and 149 (84.2%) had clear cell histology. 127 (71.8%) received nivolumab monotherapy, 40 (22.6%) received ipilimumab and nivolumab, and 10 (5.6%) received ICI with a tyrosine kinase inhibitor. ICI was given in the 1st line in 34 (19.2%) pts, 2nd line in 77 (43.5%) pts, and the 3rd or later line in 29 (16.4%) pts. The ORR was 18.6% (33/177), and there were 6 (3.4%) complete responses. The median TNT and OS was 8.9 (95% CI; 7.1-10.6) and 26.7 (95% CI; 22.4-30.9) months, respectively. In multivariate analysis (MVA) of TNT including sex, nephrectomy status, IMDC risk group, histology, and number of organs involved, only number of organs involved (HR: 1.27; 95% CI: 1.12-1.45; p = 0.0003) and non-ccRCC subtype (HR: 2.63; 95% CI: 1.63-4.24; p <0.0001) retained statistical significance. MVA of OS revealed similar findings, with number of involved organs (HR: 1.49; 95% CI: 1.97-7.45; p < 0.0001) and non-ccRCC subtype (HR: 3.83; 95% CI: 1.97-7.45; p <0.0001) correlating with worse survival. irAEs were observed in 77 pts (43.5%) with 42 (23.7%) pts experiencing a grade 3/4 irAE. Conclusions: ICI therapy is safe and efficacious in the real world setting. Clinical and laboratory variables, including the IMDC risk score, do not consistently predict outcomes in this heterogeneous cohort.

Acute interstitial nephritis (AIN) following immune checkpoint inhibitor (ICI) therapy in metastatic RCC (mRCC) as a potential predictor of response

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Background: ICIs such as nivolumab (N) have improved outcomes in mRCC patients (pts), but are also associated with immune-related adverse events. As has been shown in melanoma, we hypothesized that pts experiencing an autoimmune reaction directed against the tissue of origin may be more likely to benefit from ICI. Specifically, we evaluated whether pts with nivolumab-induced AIN (N-AIN) exhibited improved outcomes. Methods: We identified all patients with mRCC at UT Southwestern Medical Center from 2014 - 2018 who received at least one dose of N. We extracted creatinine (Cr) values over the entirety of each pt's N treatment course from the electronic medical record. Pts with a 1.5 fold Cr increase over baseline were investigated. The diagnosis of N-AIN was made by biopsy or by clinical criteria (timing of kidney injury, laboratory analysis, and exclusion of other causes). Results: We identified 177 mRCC pts who received at least one dose of N, 36 of whom had at least a 1.5 fold increase in Cr over baseline while on treatment. Of those, two had biopsy-proven AIN and one was clinically diagnosed, resulting in an incidence of 1.7%. Two received N monotherapy after first line, and the third in combination with ipilimumab as initial therapy. The earliest case of N-AIN occurred 1.5 months from N onset, and the others were diagnosed at 11 and 12 months. Of the 3 pts, one had a partial response lasting 2 years, and the other two had a complete response which is ongoing in both pts with over 2 years of follow up. In all 3 cases, N-AIN was treated with cessation of N and prednisone with a return to baseline kidney function. None required dialysis. Conclusions: AIN is a rare event with N, but it may portend a higher likelihood of response. One possible explanation is antigenic crossover between normal renal tubular cells and mRCC, resulting in a robust immune response.

Overall survival and independent review of response in CheckMate 214 with 42-month follow-up: First-line nivolumab + ipilimumab (N+I) versus sunitinib (S) in patients (pts) with advanced renal cell carcinoma (aRCC)

609

Background: N+I demonstrated superior OS and ORR v S in intention-to-treat (ITT) and intermediate/poor-risk (IP) pts with aRCC in CheckMate 214. Here, we report OS, response outcomes per independent radiology review committee (IRRC), and safety with extended min follow-up of 42 mo. Methods: Pts with clear cell aRCC were randomized 1:1 to N 3 mg/kg + I 1 mg/kg Q3W×4 and then N 3 mg/kg Q2W, or S 50 mg daily for 4 wk on, 2 wk off. Endpoints were OS, ORR, and PFS per IRRC using RECIST v1.1 in IP (primary), ITT (secondary), and favorable pts (FAV; exploratory). Results: OS remained superior in ITT (HR 0.72) and IP (HR 0.66) pts with N+I v S (Table). ORR per IRRC was higher and more responses were ongoing with N+I v S (68% v 53% [ITT] and 68% v 52% [IP]). More pts achieved complete response (CR) with N+I and these were ongoing in 86% [ITT] and 84% [IP] of pts. The PFS probability with N+I stabilized after 24 mo at ~35% in ITT and IP pts, whereas probabilities declined over time with S. Among FAV pts, while ORR was 29% with N+I v 54% with S, more pts achieved CR (13% v 6%), and more responses were ongoing (69% v 54%) with N+I v S; 94% of CRs in FAV pts were ongoing with N+I. OS benefits were similar in both arms and PFS probabilities are stabilizing with N+I and declining with S in FAV pts. The incidence of any and grade 3–4 treatment-related AEs was consistent with previous reports and no new drug-related deaths occurred in either arm. Response outcomes per investigator will also be reported. Conclusions: Superior OS and ORR with N+I v S was maintained in ITT and IP pts. More pts treated with N+I experienced CR compared with S, responses and CRs were durable, and PFS probabilities stabilized with N+I after extended follow-up. No new safety signals emerged. Clinical trial information: NCT02231749 .[Table: see text]

Combination of dual immune checkpoint inhibition (ICI) with stereotactic radiation (SBRT) in metastatic renal cell carcinoma (mRCC) (RADVAX RCC)

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Background: Dual ICI with nivolumab/ipilimumab (N/I) has become a standard of care (SOC) for patients (pts) with mRCC. Since the failure to respond to ICI may be due to a lack of immune recognition, novel vaccination approaches and stimulation of the innate immune system (e.g. stimulator of interferon genes (STING) agonists) are being pursued in clinical trials. Because preclinical studies using SBRT have demonstrated the a.) release of tumor antigens, b.) STING pathway activation and c.) synergy with ICI, we have conducted a study to explore the safety and efficacy of this approach in mRCC pts. Methods: Pts with clear cell mRCC were screened and enrolled at two sites (UT Southwestern and Johns Hopkins). Prior treatment with tyrosine kinase inhibitors (TKI) and IL2 were allowed. Enrolled pts received standard of care dosing with Nivolumab (3 mg/kg) and Ipilimumab (1mg/kg) IV q3weeks followed by nivolumab monotherapy. SBRT was administered to 1-2 disease sites with a dose of 50 Gy in 5 fractions between the first and the second dose of N/I. The primary goals of this exploratory study were to determine the safety and tolerability as well as the objective response rate (ORR) by RECIST 1.1 of non-irradiated lesions. Results: A total of 29 pts were screened and 25 pts were enrolled. 11 (44%) of pts received at least one prior systemic therapy: 4 (16%) pts received IL2 and 7 (28%) TKI therapy. The cohort was primarily intermediate and poor risk pts (favorable risk n = 2 (8%), intermediate risk n = 20 (80%), poor risk n = 3 (12%)). 10 (40%) pts required immune suppressive therapy with prednisone for classic immune related adverse events as seen with dual ICI. Radiation pneumonitis limited to the radiation field (grade 2) was seen in 2 pts and responded promptly to oral steroids. At the time of analysis, partial responses (PR) were observed in 14/25 patients with an ORR of 56%. Additional analyses including duration of response, progression free survival and overall survival will be presented. Conclusions: Dual ICI with SBRT showed an acceptable safety and encouraging antitumor activity in mRCC warranting further investigations. Clinical trial information: NCT03065179.

Final analysis of the CheckMate 025 trial comparing nivolumab (NIVO) versus everolimus (EVE) with >5 years of follow-up in patients with advanced renal cell carcinoma (aRCC)

617

Background: CheckMate 025 demonstrated superior overall survival (OS) in previously treated patients (pts) with aRCC, with improved safety and tolerability in the NIVO arm compared with EVE. The primary analysis was based on 14-months minimum follow-up. Here, we report an updated, final analysis with an extended minimum follow-up of 64 months. Methods: Previously treated pts with predominantly clear cell aRCC were randomized (1:1) to NIVO 3 mg/kg IV every 2 weeks or EVE 10 mg orally once daily until progression or unacceptable toxicity. The primary endpoint was OS. Secondary endpoints included objective response rate (ORR), progression-free survival (PFS), and safety. Confirmed ORR and PFS were per investigator (inv) using RECIST v1.1. Results: Overall, 410 vs 411 pts were randomized to NIVO vs EVE, respectively. OS benefit was maintained and PFS favored NIVO vs EVE with long-term follow-up (HR 0.84 (95% CI 0.72–0.99). (Table) ORR was higher (23% vs 4%) with NIVO vs EVE and median duration of response (DOR) was longer (18.2 vs 14.0 months). Ongoing response was observed in 28% vs 18% of pts with NIVO vs EVE. Most pts received subsequent systemic anticancer therapy: 276 pts in the NIVO arm (67%; most commonly EVE [35%] or axitinib [33%]) and 296 pts in the EVE arm (72%; most commonly axitinib [41%] or NIVO [26%]). No new safety signals or treatment-related deaths emerged with long-term follow-up in either arm. More pts in the EVE arm (37%) experienced a grade 3/4 treatment-related AE compared with pts in the NIVO arm (21%). Conclusions: At >5-years minimum follow-up, response rates and survival remain superior with NIVO vs EVE, and 28% of responses to NIVO are ongoing. Long-term follow-up highlights the efficacy and safety of NIVO monotherapy in pts with aRCC. Clinical trial information: NCT01668784. [Table: see text]

Safety and efficacy of immune checkpoint inhibitors (ICI) in metastatic non-clear cell renal cell carcinoma (nccRCC): An institutional experience

640

Background: ICIs have improved outcomes in clear cell RCC patients (pts), and emerging data suggest that they may be effective against nccRCC. nccRCC comprises ~25% of renal tumors and consist of a diverse group of diseases. Despite recent evidence, data regarding the efficacy of ICIs in nccRCC remain limited, especially among rarer nccRCC subtypes. Methods: We identified all cases of metastatic nccRCC that received at least one dose of ICI therapy at UT Southwestern Medical Center from 2014 – 2018. Baseline characteristics and IMDC criteria were evaluated at the time of ICI initiation. Outcomes included objective response rate (ORR) per RECIST v1.1 criteria, time to next treatment (TNT), and overall survival (OS). Immune-related adverse events (irAE) were graded per CTCAE 4.0 criteria. Survival estimates were evaluated using Kaplan Meier methods. Results: We identified 28 pts with metastatic nccRCC; 12 (42.9%) unclassified RCC (uRCC), 8 (28.6%) papillary RCC (pRCC), 3 (10.7%) chromophobe RCC (chRCC), 3 (10.7%) hereditary leiomyomatosis and renal cell cancer (HLRCC), 1 (3.6%) translocation RCC (tRCC) and 1 (3.6%) acquired cystic disease-associated RCC (ACD-RCC). 23 (82.1%) pts were intermediate or poor risk by IMDC criteria. In total, 13 (46.4%) pts received nivolumab monotherapy, and 15 (53.6%) in combination with ipilimumab. 12 (42.9%) pts received ICI in the first line. The median TNT and OS amongst all nccRCC subtypes was 4.9 (95% CI: 1.7-8.1) and 15.9 (95% CI: 5.9 – 25.9) months respectively. The ORR was 3/28 (10.7%), with 2 complete responses. All responses were restricted to the pRCC and uRCC subtypes. 11 (39.3%) pts experienced any irAE and 5 (17.9%) had a grade 3/4 irAE, including one case of grade 4 myocarditis. The median time to onset of an irAE was 1.9 months (Range: 0.1 to 12.0). At a median follow up of 10.8 months (95% CI: 10.2 – 17.9), 4 pts remain on therapy and 13 pts have died. Conclusions: ICI therapy demonstrated modest efficacy in this cohort with comparable irAE profiles to ccRCC. Objective responses were not seen in pts with HLRCC, ACD-RCC, tRCC, or chRCC in this study.

An exploratory study of 89Zr-DFO-Atezolizumab ImmunoPET/CT in patients with locally advanced or metastatic renal cell carcinoma

TPS759

Background: Immune checkpoint inhibitors (ICIs) have changed the treatment landscape for renal cell carcinoma (RCC). Despite this, responses to single-agent anti-PD-1 occur in only 25% of patients. Biomarkers such as PD-L1 expression and tumor infiltrating lymphocyte density may predict response, but require invasive biopsies that fail to fully interrogate the complex tumor microenvironment throughout the patient. Efforts are underway to identify who will benefit from ICIs. Among these are the use of radiolabeled antibodies against PD-L1. We propose to combine the specificity of anti-PD-L1 antibodies with the sensitivity, resolution, and quantification offered by positron emission tomography to develop immunoPET (iPET). iPET will allow real-time monitoring of tumor and its microenvironment in-vivo, and may correlate with response and toxicity with ICIs. Methods: The anti-PD-L1 antibody Atezolizumab is conjugated to Zirconium-89 via desferrioxamine (DFO). 89Zr-DFO-Atezolizumab will be administered to two cohorts of approximately 20 patients. Cohort 1 have localized RCC prior to undergoing surgery, and cohort 2 have metastatic RCC prior to treatment with an ICI. The main exclusion criteria are existing use of an ICI or comorbidities that would preclude treatment with an ICI. All subjects will receive an IV injection of 89Zr-DFO-Atezolizumab followed 7 days (+/- 1 day) by a PET/CT scan. Subjects in cohort 2 will receive treatment with ICI per clinician discretion. Subjects will receive a repeat scan if disease recurrence is documented (cohort 1) or should progression or toxicity occur after treatment with an ICI (cohort 2). Biopsy of disease recurrence (cohort 1) will be standard, and encouraged for sites of disease progression on ICI (cohort 2). Co-primary endpoints are an exploratory analysis of 89Zr-DFO-Atezolizumab uptake on PET/CT with PD-L1 expression assessed by IHC in patients undergoing surgery (cohort 1) and to evaluate uptake across metastatic sites and explore the relationship with response or toxicity with ICI therapy (cohort 2). An investigational new drug approval has been granted for 89Zr-DFO-Atezolizumab (IND 143266) and accrual commenced 1 October 2019. Clinical trial information: NCT04006522.